Sample Size Computation Research Articles

Protocol for the LIFEH project: a prospective observational study to explore lifestyle among people living with HIV experiencing weight gain, looking beyond antiretroviral therapy

IntroductionWeight gain, together with the onset of overweight and obesity, is a relevant emerging health issue among people living with HIV (PLWH). A large body of literature recognises this issue...

Effect of Human Resource Management Practices on the Growth of Small and Medium Scale Enterprises in Kaduna State

This study examined the effect of human resource management practices on the growth of small and medium scale enterprises in Kaduna state. The study employed descriptive survey design while primary data was used through the administration of structured questionnaire as the source and method of data collection for the study respectively. The population of the study comprises of one hundred and fifty (150) staff from the various SMEs in Kaduna state. The adjusted sample size of the study was computed to be 120 participants using Taro Yamane formula for sample size computation through the use of census as the sampling technique of the study. The data obtained from the respondents were presented using frequency tables, percentages and linear regression (Pearson Correlation). The findings from the study revealed that the independent variables proxied by recruitment and selection, training and development, motivation and remuneration jointly have significant effects on the growth of SMEs in Kaduna State. It is therefore, concluded that human resource management practices is a good driver of SMEs growth in Kaduna State. Therefore, it is recommended that employees who offer the same level of inputs with respect to skills, efforts, qualifications, experience, should be entitled to equitable outcomes in terms of pay, promotion, job security, and opportunity for advancement. Most importantly, additional inputs and outstanding performance should entitle an employee to additional rewards. This study underscores the need for government at all levels as well as the Non-Governmental Organizations to come up with a blue-prints designed at empowering the Small and Medium Scale Business Enterprises in terms of survival funds, recruitment, training, remuneration, and overall human resource management practices with a view to drastically unemployment among youths in Kaduna State, and Nigeria at large.

The science and art of biostatistics: a comprehensive overview

Biostatistics is the area that involves the application of statistical methods to biological and health-related research and draw out valid conclusion from the obtained data. Statistics are essential to clinical trials and the drug development process, from trial design to protocol preparation. Providing a basic awareness of statistical concerns can help maintain the credibility of a clinical trial. Biostatistics is used at every stage of clinical research, including trial design, protocol development, data tracking and management, data processing, and trial reporting. This article deals with bringing in frame the basic biostatistical concepts that are significant and convenient in analyzing various types of data observations that includes the types of data, measure of central tendency, measure of dispersion, parametric and non-parametric test. Other parameters, such as the normal distribution, sample size computation, significance level, null and alternate hypothesis, and statistical significance test, are thoroughly discussed with appropriate illustrations. The review also mentions the software applications and websites helpful for statistical computations.

Sample Size Estimation in Clinical Trials

Sample size estimation remains as a cornerstone in the meticulous planning and execution of clinical trials, pivotal for ensuring studies possess the requisite statistical power to discern meaningful treatment effects. Insufficient sample sizes compromise the robustness of findings, whereas excessively large samples inflate costs and compromise data integrity. This article meticulously explains the multifaceted factors that outline sample size determination, encompassing various factors such as research design, types of hypotheses, error thresholds, effect size considerations, validity and precision. It investigates into the scope of methodologies available for sample size computation, spanning from intricate statistical formulas to pragmatic tabular approaches. Moreover, it underscores the significance of post-hoc power analysis in retrospectively evaluating completed studies, shedding light on their statistical robustness. This literature review furnishes a nuanced understanding of the sample size estimation landscape in clinical trials, delineating their strengths, limitations, and real-world applications. Anticipating participant attrition assumes paramount importance for proactively adjusting sample sizes, ensuring studies remain methodologically sound. Equipped with a profound grasp of these principles, researchers are empowered to conduct scientifically rigorous and impactful clinical trials, furnishing compelling evidence to inform judicious decision-making in healthcare interventions.

Exploring the Investment Behaviour of Petty Traders in Sunyani Municipality

Purpose: The primary goals of the study are to assess the level of awareness among small merchants in Sunyani Municipality regarding investment prospects, the sources of investment information, and the impact of demographic characteristics.
 Methodology: Questionnaires were employed in gathering data for the study, which was based on the quantitative research approach. Using Slovin's sample size computation, a sample size of 396 respondents was selected for the investigation.
 Findings: The results revealed that the majority of small traders were aware of prospective investment alternatives such as real estate, government bonds, bank deposits, life insurance, mutual funds, and stocks and shares. It was discovered that the traders had access to two information sources: the formal and informal sectors. The survey discovered that friends and family serve as the key informal sources of information. Regarding the formal sector, it is disclosed that radio and television served as their sources of investment-related information. Also, the degree of awareness regarding investment opportunities was influenced by gender, age, and household size. The findings indicate that among the investment avenues available to traders, gold and other minerals are not well-known by traders.
 Unique contributor to theory, policy and practice: Therefore, it is recommended that programs and talk shows are organized for people to be aware of these avenues. Policymakers should prioritize programs focused on enhancing the financial inclusion of petty traders by improving the accessibility of formal financial services such as savings accounts, credit facilities, and insurance products. The research findings could potentially aid in improving financial inclusion for small-scale traders, informing local government policies that support them, providing valuable market intelligence for businesses targeting this demographic, and contributing to academic knowledge in the fields of economics, finance, and development studies.

A Comparison of Psychological Distress and Coping Styles among Physicians and Nurses in a COVID-19 Referral Hospital in Manila: A Cross-sectional Study.

This study aimed to compare the levels of depression, anxiety, and stress, and the coping styles among physicians and nurses in a COVID-19 referral hospital in Manila from June to July 2020. A cross-sectional study among medical residents and nurses selected via convenience sampling was employed. Data were obtained through COVID Stressors and Stress Reduction Questionnaire, Depression, Anxiety, and Stress Scale-21, and Filipino Coping Strategies Scale. Descriptive and inferential analysis of data was done. Five hundred seventy-one (571) healthcare workers (total population: 1,650 nurses and physicians) participated in the study, representing 81.6% of the computed sample size of 700 respondents. Among the participants, 60.6 %, 69.0%, 48.9% reported symptoms of depression, anxiety, and stress, respectively. Nineteen percent (19%) of nurses reported severe to extremely severe depression, and 42.0% reported severe to extremely severe anxiety. In contrast, 30.8% of residents reported severe to extremely severe depression, and 28.4% conveyed severe to extremely severe anxiety. There was no association observed between perceived levels of stress between the two healthcare professions.There were more mildly to extremely severe anxious healthcare workers in the COVID areas (74.6%) compared to the non-COVID areas (61.2%). Differences in coping styles were observed among the participants' clinico-demographic characteristics. Top healthcare worker stressors include being negligent and endangering co-workers (88.6%), frequent modification of infection control procedures (87.0%), and discomfort from protective equipment (81.4%). Top stress-reducing factors include provision of food and vitamins (86.7%), sufficient rest (84.2%), and support from higher-ranking colleagues (73.7%). This study has shown that more than half of the healthcare workers reported mild to extreme levels of depression and anxiety, while a little less than half reported mild to extreme levels of stress. The development and implementation of hospital interventions and programs based on the sources of distress and stress-reducing factors is recommended to mitigate the impact of sustained psychological distress on mental health and physical wellbeing of hospital healthcare workers.

Internal Control and Financial Performance of Accounting Firms in Calamba City

Internal control implementation in accounting firms ensures the integrity of financial information, safeguards assets, and mitigates risks, promoting operational efficiency and compliance with regulatory standards. The main thrust of this study was to describe and determine the relationship between the level of internal control implementation and the financial performance of accounting firms in Calamba City. This study employed a descriptive correlational design and utilized a simple random sampling technique to select the sample, enabling the researcher to obtain representatives from the population. With the aid of the Gpower sample size computation application, this study came up with 80 respondents based on a 0.35 effect size and 95% degrees of confidence. As the primary data collection tool, a validated researcher-made questionnaire was utilized. The data gathered were collected, tallied, analyzed, and interpreted using four-point Likert scales, mean, and Pearson Product-Moment Correlation Coefficient. Based on the results of the study, the internal control of accounting firms in Calamba City was fully implemented, and their financial performance was very high, with a general assessment of 3.43 and it explained that these accounting firms have a definite process and procedures for assessing financial information of the customers to secure and to maintain good financial performance among other competitors in the market. As an output of the study, a proposed action plan based on the COSO framework was proposed to improve the quality of the control environment, risk assessment, information and communication, control activities and monitoring procedures, and improve the financial performance of accounting firms in Calamba City.

Assessment of Awareness and Approach Regarding Antibiotic Prescription and Resistance among Different Level of Dental Students in a Tertiary Care Dental College, Karachi

OBJECTIVE: To evaluate the awareness and approach of dental students regarding antibiotic prescription and its resistance due to irrational use of antibiotics. Antibiotic resistance is spreading alarmingly throughout the world, including developed countries. The common causes of antibiotic resistance include over prescription, incomplete treatment and inappropriate self medication.Among different causes of antimicrobial resistance, irrational use of antibiotic is the most prominent one. METHODOLOGY: After approved by the Institutional Ethics Committee of Ziauddin University this cross-sectional study was conducted from 1st April, 2020 to 30th July,2020 at Ziauddin University. Third and final year dental students as well as house officers were enrolled and the computed sample size was 133 to which 5% non-response rate was added, therefore total 139 dental students were approached. Non-probability convenience sampling technique was used. A self- designed, self administered questionnaire was prepared to collect the demographic data and information regarding the prescription pattern of antibiotics amongst study subjects. All questions in the questionnaire were close ended. The questionnaire comprised information pertaining to demographic characteristics, standard guideline for antibiotic prescriptions, antibiotic stewardship and resistance, improper prescription and its consequences. The dental students were briefed about the purpose of the study and the significance of participation and a written informed consent was obtained from them. The awareness of dental students regarding antibiotics was the outcome factor. The data was analyzed by using SPSS version 22. RESULTS: Out of total 139 dental students majority (79.1%)were familiar to standard antibiotic prescription guidelines .(87.8%) responded amoxicillin is beta lactam, for probability of antibiotic abuse and antibiotics aid in recovery of infections majority showed awareness (92.1% and 84.9% respectively). Almost equal students inquire recent antibiotic course prior to prescription (90.6%) as well as take extra caution prescribing antibiotic in immune compromised patients (89.9%). CONCLUSION: This study concluded that majority of the dental students had good awareness regarding antibiotics and factors related to it, as participants responded positively to the 70% of awareness - based questions. KEYWORDS: Awareness. Antibiotics, Resistance, Prescription, Dental Students

Sample size planning for multiple contrast tests.

Sample size calculations for two (independent) samples are well established and applied in (pre-)clinical research. When planning several samples, which is common in, for example, preclinical studies, sample size planning tools based on analysis of variance methods are available. Since the underlying effect sizes of these methods are often hard to interpret and to provide for the sample size planning, we employ multiple contrast test procedures for sample size computations in both parametric (under normality assumption) and nonparametric designs using Steel-type tests. Since the exact distributions of the test statistics are unknown under the alternative and variance heterogeneity, we use approximate solutions. Furthermore, since no closed formula for the sample size is available, we use numerical approximations for their computation. Extensive simulation studies are finally conducted to assess the quality of the approximations. It turns out that the methods are accurate in the sense that the multiple contrast test procedures reach the target power to detect the alternative of interest with the sample size computed. The developed procedures are a valuable tool to plan (pre-)clinical trials with several samples and are easily accessible in publicly availablesoftware.

Frequency of Inferior Alveolar Nerve Damage After Open Reduction and Internal Fixation in Mandibular Fractures

One of the most frequent injuries to the maxillofacial region is mandibular fracture. Numerous places experience fractures. The inferior alveolar nerve is often injured as a result of mandibular fractures. Objective: To ascertain how frequently patients in the oral and maxillofacial department of the Ayub Teaching Hospital in Abbottabad experienced inferior alveolar nerve injury following open reduction and fixation of a mandibular fracture. Methods: This was a Descriptive case series carried out at Oral and Maxillofacial Department, Ayub Teaching Hospital, Abbottabad after approval from the IRB of the institution and CPSP vide number (CPSP/REU/DSG-2018-010-2532). Using the formula to evaluate proportion with absolute precision and the following premises, the sample size was determined to be 96 using the WHO software for sample size computation in health studies: The expected percentage of inferior alveolar nerve injury following fixation in mandibular fracture is 45%, the confidence level is 95%, and the absolute precision is 10%. Results: The mean age of participants was 35.81±5.63 years with range from 26 to 45 years. Most common age group was 36-40 years and 41-45 years (n=26, 27.08%) followed by 26-30 years (n=23, 23.96%). There were 70 (72.92%) males and 26 (27.08%) females in the study. Majority (n=88; 91.67%) of the patients were given general anesthesia while the remaining (n=8; 8.33%) received local anesthesia. Perioperative inferior alveolar nerve injury was observed in 56 (58.33%) patients while permanent inferior alveolar nerve injury was diagnosed in 39 (40.63%) patients. Conclusions: Damage to inferior alveolar nerve is a frequent problem of open reduction and fixation of mandibular fracture. However, utmost care should be exercised to reduce its occurrence in patients with mandibular fracture.

A general Monte Carlo method for sample size analysis in the context of network models.

We introduce a general method for sample size computations in the context of cross-sectional network models. The method takes the form of an automated Monte Carlo algorithm, designed to find an optimal sample size while iteratively concentrating the computations on the sample sizes that seem most relevant. The method requires three inputs: (1) a hypothesized network structure or desired characteristics of that structure, (2) an estimation performance measure and its corresponding target value (e.g., a sensitivity of 0.6), and (3) a statistic and its corresponding target value that determines how the target value for the performance measure be reached (e.g., reaching a sensitivity of 0.6 with a probability of 0.8). The method consists of a Monte Carlo simulation step for computing the performance measure and the statistic for several sample sizes selected from an initial candidate sample size range, a curve-fitting step for interpolating the statistic across the entire candidate range, and a stratified bootstrapping step to quantify the uncertainty around the recommendation provided. We evaluated the performance of the method for the Gaussian Graphical Model, but it can easily extend to other models. The method displayed good performance, providing sample size recommendations that were, on average, within three observations of a benchmark sample size, with the highest standard deviation of 25.87 observations. The method discussed is implemented in the form of an R package called powerly, available on GitHub and CRAN. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Risk factors for dating violence among undergraduates in selected state universities in the Western Province, Sri Lanka

Introduction: Dating violence (DV) is an important public health concern globally, although it has been given a low level of recognition in Sri Lanka. Objectives: To determine risk factors for DV among undergraduates in selected universities in Western Province, Sri Lanka Methods: A case control study (Phase II) was conducted as part of a large study (Phase I). Cases and controls were those with and without DV among those who reported heterosexual relationships for a duration of six months or more before the survey. Computed sample size was 200 in each group. Cases and controls were randomly selected from Phase I. Data were collected using a validated, anonymous, self-administered questionnaire. Adjusted odds ratios (AOR) were determined using multiple logistic regression. Results: Risk factors identified were female sex (AOR=2.6; 95% CI: 1.1, 6.1; p=0.03), father's low educational level (AOR=3.1; 95% CI: 1.2, 7.6; p=0.02), presence of community violence (AOR=8.5; 95% CI: 3.2, 22.2; p<0.01), watching pornography (AOR=19.8; 95% CI: 7.7, 50.8; p<0.01) and sexual abuse in childhood (AOR=22; 95% CI: 3.1, 154.8; p<0.01). Spending time with friends (AOR=0.1; 95% CI: 0.04, 0.3; p<0.01) was a protective factor. Presence of family conflicts (p=0.4), monthly income below Rs. 25000/= (p=0.4), non-engagement in extracurricular activities (p=0.4) and substance abuse of the respondents (p=0.8) were not significantly associated with dating violence. Conclusions & Recommendations: Sex, paternal education, community violence, pornography and childhood sexual abuse were the risk factors identified of DV. It is recommended to help undergraduates to handle exposure to factors in the surrounding environment which promotes development of violent ideas.

Robust nonparametric hypothesis tests for differences in the covariance structure of functional data

AbstractWe develop a group of robust, nonparametric hypothesis tests that detect differences between the covariance operators of several populations of functional data. These tests, called functional Kruskal–Wallis tests for covariance, or FKWC tests, are based on functional data depth ranks. FKWC tests work well even when the data are heavy‐tailed, which is shown both in simulation and theory. FKWC tests offer several other benefits: they have a simple asymptotic distribution under the null hypothesis, they are computationally cheap, and they possess transformation‐invariance properties. We show that under general alternative hypotheses, these tests are consistent under mild, nonparametric assumptions. As a result, we introduce a new functional depth function called ‐root depth that works well for the purposes of detecting differences in magnitude between covariance kernels. We present an analysis of the FKWC test based on ‐root depth under local alternatives. Through simulations, when the true covariance kernels have an infinite number of positive eigenvalues, we show that these tests have higher power than their competitors while maintaining their nominal size. We also provide a method for computing sample size and performing multiple comparisons.

The hidden factor: accounting for covariate effects in power and sample size computation for a binary trait.

Accurate power and sample size estimation is crucial to the design and analysis of genetic association studies. When analyzing a binary trait via logistic regression, important covariates such as age and sex are typically included in the model. However, their effects are rarely properly considered in power or sample size computation during study planning. Unlike when analyzing a continuous trait, the power of association testing between a binary trait and a genetic variant depends, explicitly, on covariate effects, even under the assumption of gene-environment independence. Earlier work recognizes this hidden factor but the implemented methods are not flexible. We thus propose and implement a generalized method for estimating power and sample size for (discovery or replication) association studies of binary traits that (i) accommodates different types of nongenetic covariates E, (ii) deals with different types of G-E relationships, and (iii) is computationally efficient. Extensive simulation studies show that the proposed method is accurate and computationally efficient for both prospective and retrospective sampling designs with various covariate structures. A proof-of-principle application focused on the understudied African sample in the UK Biobank data. Results show that, in contrast to studying the continuous blood pressure trait, when analyzing the binary hypertension trait ignoring covariate effects of age and sex leads to overestimated power and underestimated replication sample size. The simulated datasets can be found on the online web-page of this manuscript, and the UK Biobank application data can be accessed at https://www.ukbiobank.ac.uk. The R package SPCompute that implements the proposed method is available at CRAN. The genome-wide association studies are carried out using the software PLINK 2.0 [Purcell et al. (Plink: a tool set for whole-genome association and population-based linkage analyses. Am J Hum Genet 2007;81:559-75.)].

Simulation of Copper Nanowire by Comparing its Volume and Alignment range using Composite Filament Simulation 3D to predict the Resistivity of the Nanowire

Aim: In this research work the simulation of electrical resistivity of copper nanowire by using a Novel Composite Filament Simulation Tool, and comparing the resistivity by its Volume and Alignment range. Materials and Methods: This review was done at the Simulation research lab, Saveetha School of Engineering, Chennai. The sample size computation was finished by past outcomes using clinical.com by keeping alpha error-threshold by 0.05, enrollment ratio as 0:1, 95% confidence interval, power at 80%. Group 1 and 2 are volume (N=20) and alignment range (N=20) of copper nanowire. The complete sample size was 50. Results: Comparison between these two parameters are done by independent sample test using SPSS software. There is a statistical indifference between volume and in alignment range. Copper nanowire based on its volume (55%) showed higher resistivity in comparison to its alignment range (50%). There appears to be a statistically significant difference (p=0.047, p<0.05) by using an independent sample T test. Copper nanowire having volume a high showed better results in comparison to its alignment range. Conclusion: Copper nanowire by volume appears to give better electrical resistivity than its alignment range.

Analysis and Comparison of Image Enhancement Techniques for Improving PSNR of Liver Images by Median Filtering over Mask Filtering

Aim: The goal of this research is to employ median filters and mask filters to reduce noise in liver images so that they can be improved. In addition, the Peak Signal to Noise Ratio of both filters’ outputs was examined (PSNR). Materials and Methods: The afflicted and normal liver photos were obtained from the Kaggle website for this investigation. Then, using Matlab software, the mask filtering and median filtering algorithms were run. Clinicalc. com was used to compute sample size, and SPSS software was used to conduct the comparative analysis. This study has two groups, each with a sample size of 20 people with an average G power of 80%. The innovative median filter’s performance is assessed, and the PSNR performance metric is compared to that of the mask filter. Results: The PSNR of innovative median filters is 64.0310, while mask filters have a PSNR of 78.0095, according to Matlab simulation data. The significant value of PSNR (Peak Signal to Noise Ratio) (0.409) and p>0.05 was found in the statistical analysis. Conclusion: The innovative median filter delivers greater PSNR than the mask filter for medical image enhancement on ultrasound liver pictures, according to this study.

Frequency of Left Ventricular Mechanical Dyssynchrony in Chronic Heart Failure

Objective: To determine the frequency of left ventricular mechanical dyssynchrony in chronic heart failure patients. Material and Methods: After approval from the Hospital ethical committee, the study was conducted in the department of cardiology Hayatabad medical complex Peshawar from 1st September 2021 to 28th February 2022. In this descriptive cross-sectional study, 155 patients in total were examined while 27% of heart failure patients had mechanical dyssynchrony, a 95% confidence interval, and a 7% margin of error were maintained according to WHO sample size computations. Results: This study's participants had an average age of 60, with a standard deviation of ±1.26 years. 62% of the patients were male, compared to 38% of females. 35% of patients had a Broad QRS complex, whereas 65% of patients had a Narrow QRS complex. Mechanical dyssynchrony was identified in 32% of chronic heart failure patients. Conclusion: Patients in chronic heart failure with QRS > 150ms and having mechanical dyssynchrony are benefited with Cardiac Ressynchronisation Therapy (CRT) implantation which reduces morbidity and mortality, while those with a narrow QRS (<150ms) are generally non – responders. Keywords: Mechanical dyssynchrony, chronic heart failure, left ventricular ejection fraction

Measuring the impact of CSR practices on customer satisfaction during pandemic: a quantitative study in the Philippines

PurposeThis study aims to analyze how consumers perceive the corporate social responsibility (CSR) practices carried out by a local water district in Angeles City, Philippines. The main objective of the study is to investigate how CSR practices influence customer satisfaction. To achieve this, several pieces of literature were mentioned to prove that CSR has an important role to its stakeholders.Design/methodology/approachThe study used a descriptive and quantitative approach to test the hypotheses. The participants of the study were the residents of the top three barangays in Angeles City, Philippines, in terms of the most consumed water supply, namely: Cut-cut, Pampang and Anunas. Using the Raosoft sample size calculator, the computed sample size was 382 respondents and distributed using stratified sampling. Methodologically, the study used statistical treatment to test all the variables and validated the instrument.FindingsThe result of the study shows that CSR practices significantly impact customer satisfaction. In the test of the degree of relationship between the dimensions of CSR and customer satisfaction, it was found that there is a significant relationship between the two variables.Research limitations/implicationsThe future study may explore the relationship between CSR and the resource-based view theory of the firm. The resource-based perspectives are useful to understand why firms engage in CSR activities and disclosure. From a resource-based perspective, CSR is seen as providing internal or external benefits, or both.Practical implicationsThe water district must promote social welfare and behave as good corporate citizens; they must spend the resources allocated to CSR initiatives in ways that yield optimum benefits to society as well as to the stakeholders of the company.Social implicationsThe paper points out that the water supply industry is one of the most regulated sectors, as the operation requirements are tighter than any other activity. The authors emphasize that water companies must assume special responsibility because their activities are directly related to the use of natural resources, environmental pollution, and public health.Originality/valueThis study used a descriptive-explanatory strategy to determine the significant variables using PLS-SEM. This paper addressed how consumers perceive the CSR practices carried out by the local water district in Angeles City, Philippines.

Avoiding the Removal of Syndesmotic Screws after Distal Tibiofibular Diastasis Repair: A Benefit or a Drawback?

There is still no general agreement about the most effective form of syndesmosis fixation with syndesmotic screws for patients affected by ankle fractures that are accompanied by syndesmotic injuries. In the same manner, no consensus has been reached yet on whether or not the tibiofibular syndesmotic screw is more beneficial if removed or not, as well as the exact timing of removal if this proves superiority. The purpose of this research was to verify whether or not removing syndesmotic screws reduces the risk of developing a diastasis and compare outcomes in patients whose syndesmotic screw was or was not removed at all. A retrospective observational study was carried out to cover a period of five years and a computed sample size of almost 300 cases. Patients were included in the current study if their history was positive for ankle fracture with distal tibiofibular diastasis repair with syndesmotic screws. Loss of reduction was more frequent after screw removal (8.5% vs. 2.1%), although the quality of reduction was generally excellent in both groups. The mean AOFAS score was significantly better in patients who had their tibiofibular screw removed (92.6 vs. 88.4), but the tibiofibular clear space and incisura fibularis depth widened more following the second intervention (3.8 mm vs. 3.6 mm, and, respectively, 4.3 vs. 4.1). Lastly, the same patients with tibiofibular screw removal had a significantly higher cost of total interventions and more days of medical leave (21 vs. 15 days on average). It seems that a strong conclusion in favor of removing or not removing syndesmotic screws after distal tibiofibular diastasis repair cannot be given. However, several radiographic findings lean toward the benefit of those patients whose tibiofibular screws were not removed, although mobility was notably better after the screw was removed. Furthermore, treatment expenses are greatly lowered if a subsequent operation for screw removal is avoided, as well as if individuals who have a single surgery take a shorter medical leave.

SAMPLING METHODS AND APPROPRIATE SAMPLE SIZE DETERMINATION: A CONCISE OVERVIEW

Sample size determination has been a controversial issue for many applied researches, such that incorrect determination of how large a sample should be may lead to erroneous inferences in the study. For this reason, in this paper it has been aimed to highlight the general criteria and formulations for detecting the required minimum sample size especially in probability sampling methods -which can be summarized as simple random sampling, systematic sampling, stratified sampling and cluster sampling- and various research designs. Besides, the place of statistical power and effect size on sample size determination and the sample size computations for regression analysis based on the study by Cohen (1988) have also been mentioned.