Fisher 's Least Significant Difference Research Articles

Effect of seed bed types on growth and yield of onion seedlings (Allium cepa L.) Under the influence of fertilizer types in Makurdi, Nigeria

Field experiments was conducted at the Teaching and Research Farm, Joseph Sarwuan Tarka University Makurdi to evaluate the effect of bed types and fertilizer types on the growth and yield of onion seedlings/bulbs (Allium cepa L.). The study was a 2x4 factorial experiment {2 types (bed and ridge) and four fertilizer types (NPK20:10:10, poultry manure, cattle dung, and no application served as control)} laid out in a Randomized Complete Block Design (RCBD) replicated thrice. Data were collected were subjected to Analysis of Variance (ANOVA) and Fisher's least significant difference (FLSD) was used to separate means. Results of the study revealed that onions raised on beds had statistically higher growth and yield parameters than the ridge bed system. Therefore, the onion planted on bed type system recorded the highest yields with bulb weight (13.45t/ha) and (23.35 t/ha) in both years. On the fertilizer types, NPK 20:10:10 application recorded the highest bulb weight of 14.57t/ha and 35.75t/ha in both years, followed by poultry manure with bulb weight of 11.29t/ha and 11.61t/ha and cattle dung with bulb weight of 10.70t/ha and 12.94t/ha while untreated (control) gave the lowest yields with bulb weight/plot 9.21t/ha and 7.40t/ha respectively. It is recommended that the application of NPK 20:10:10 fertilizers on bed type system be adopted for optimum yield of Onions in Makurdi, Nigeria. Furthermore, in the scarcity or high cost of NPK fertilizers, smallholder farmers in the study location can adopt either poultry manure or cattle dung as a substitute to boost yields of onions.

A discussion and evaluation of statistical procedures used by JIMB authors when comparing means.

The aim of this work was to review and recommend statistical procedures for Journal of Industrial Microbiology and Biotechnology authors who often compare the effect of several treatments on microorganisms and their functions.

Environmental impact of quarrying on air quality in Ebonyi State, Nigeria

AbstractThe insatiable demand for rock supplies has enticed numerous building and construction enterprises to participate in stone quarrying. This paper examines the environmental impact of quarrying on air quality in Ebonyi State, Nigeria. To achieve the main aim of the study, an objective was set to detect air pollutants at the quarry sites. A total of 220 air samples were measured from six points around the quarry locations and recorded in situ for analysis. The samples were measured three times a day (morning, afternoon, and evening) for three days. Gas monitors were used to monitor air pollutants. The generated data were subjected to completely random design (CRD) sampling techniques. The separation of means and tests was performed using Fisher's Least Significant Difference (FLSD) at a significance probability level of 5%. Based on statistical analysis, the findings detected significantly higher concentration levels of particulate matter, nitrogen dioxide, hydrogen sulfide, carbon monoxide, sulfur dioxide, chlorine, volatile organic compounds, ammonia, and hydrogen cyanide in the quarry areas than the value detected in the control area. The findings also confirmed higher noise levels in the locations. It was also observed that the concentration levels of the parameters differed from point to point and at different times of the day. This really means the occurrence of a high rate of air pollution in the study locations. Based on the above findings, it is highly recommended that air pollution control equipment be installed at quarry sites in order to reduce gaseous (pollutant) emissions.

Profitability of the use of poultry manure for cucumber (Cucumis sativus L.) production in Iwollo, Southeastern Nigeria

A field experiment was conducted at the Teaching and Research Farm of Enugu state polytechnic, Iwollo, Southeastern Nigeria in 2020 to evaluate the profitability of the use of poultry manure for cucumber production in the area. The study was carried out in a randomized complete block design (RCBD) with four replications. The treatment comprised different rates of poultry manure viz; 0 (control), 5, 10, 15 and 20 t ha-1. The growth and yield parameters investigated were vine length, number of branches per plant, number of leaves per plant, leaf area index, number of fruits per plant, fruit yield per plant and fruit yield per hectare. The data collected on growth and yield parameters were subjected to analysis of variance (ANOVA) and treatment means were separated using Fisher's least significant difference (F-LSD) at 5% level of probability. Gross margin (GM) as well Return on Investment (RoI) was calculated to determine the profitability. The results showed that poultry manure significantly (p<0.05) induced higher vine length, number of branches per plant, number of leaves per plant, leave area index, number of fruits per plant, fruit yield per plant and fruit yield per hectare compared to control (0 t/ha) with optimum values obtained in 20 t ha-1. The profitability of the use of poultry manure increased with increase in the rate of poultry manure. The highest gross margin (N 3,233,860) was obtained from 20 t ha-1 of poultry manure followed by 15 t ha-1 (N 2,021,020), 10 t ha-1 (N 1,381,748), 5 t ha-1 (N 588,300) and 0 t ha-1(N14,660). Similarly, the highest RoI was obtained in 20 t ha-1 of poultry manure (325.95%) followed by 15 t ha-1 (237.49%); 10 t ha-1 (185%); 5 t ha-1 (93%) and the lowest was in 0 t ha-1 (2.76%). It could be concluded from the study that the use of poultry manure for cucumber production in Iwollo is profitable and most profitable when 20 t ha-1 is used.

Effects of slaughter house wastes on soil properties and cocoyam corm yield in Abakaliki, Nigeria

A research was carried out in research and teaching farm of, Ebonyi State University, Abakaliki to determine effects of different rates of slaughter house wastes on soil properties and cocoyam corm yield. Four rates of slaughter house wastes namely 0 (control), 3, 6 and 9 t ha‒1 were used as amendment. Soil and cocoyam were analysed using analysis of variance and differences between treatment means detected using Fisher's least significant difference (FLSD) at 5% probability level. Results from the study showed that slaughter house wastes application significant (P < 0.05) improved soil properties and cocoyam corm yield compared to control. Also, the higher the application of slaughter house wastes in the plots, the higher the improvements in soil properties though not all the improvements were significant (p < 0.05). Slaughter house wastes significantly increased cocoyam corm yield compared to control.

HEIGHT AS AN INDICATOR OF ECONOMIC STATUS IN THE POLISH TERRITORIES UNDER RUSSIAN RULE AT THE TURN OF THE 19TH TO 20TH CENTURY

Height is regarded as one of the indicators of environmental stress at population level, being an excellent barometer of standard of living. The aim of this study was to describe diversity in height among populations living in different regions of the Kingdom of Poland in terms of the economic factors in the second half of the 19th and early 20th century. This study examines the height of adult inhabitants from five guberniyas (provinces) of the Kingdom of Poland (Łomża, Warsaw, Radom, Kalisz and Płock) collected in the years 1897-1914 (N = 732 men, N = 569 women). Differences in average height of male and female inhabitants across the five guberniyas were examined using ANOVA and the Fisher's LSD (Least Significant Difference) test of multiple comparisons. Statistically significant differences in the height between the guberniyas were observed. Diversity in the economic development in the studied guberniyas of the Kingdom of Poland translated into differences in the height of their inhabitants. Moreover, an increase in mean height over time was noted.

Concentration of Fluoride and Arsenic in Bottled Drinking Water in Durango City, Mexico

Arsenic and fluoride are elements known to cause human health problems and it has been documented that both elements are found in high concentrations in the Guadiana Valley aquifer, in the state of Durango, Mexico. Since underground water is the source for potable water bottling companies commercialized in Durango City; such high concentrations reduced the quality of bottled water for human consumption according to NOM-041-SSA1-1993. Legislation establishes a maximum permissible limit (MPL) of 0.7 mg/L for fluoride and 0.025 mg/L for arsenic. In this research the main objective was to evaluate the quality of bottled water expended in Durango City with respect to the well from which water is extracted. Findings showed that the highest fluoride concentration was 5.86 mg/L (8.4 times MPL), with 100% of sampled brands exceeding the MPL (range: 1.09 to 5.86 mg/L). On the other hand, for arsenic, the highest concentration was 0.076 mg/L (threefold), with 38% exceeding the MPL (range: 0.001 to 0.076 ppm). Statistical analysis showed significant differences only for fluoride, according to Fisher LSD (Least Significant Difference) test, with an F value of 14.5 at a p value of 0.0005. According to the comparison between the quantified concentrations in bottled water and groundwater, it was found that groundwater was subjected to treatment; however, although a significant decrease in fluoride and arsenic concentration was observed, the removal processes used were not efficient to meet set standards.

Influence of varied surface texture of dentin porcelain on optical properties of porcelain specimens

Differences in the texture of dentin porcelain surfaces may change the direction of incident light at the enamel-dentin porcelain interface and affect the optical properties of a ceramic crown. The purpose of this study was to measure optical parameters of enamel-dentin porcelain complexes with different dentin porcelain surface textures, and to analyze the relationship between optical parameters and surface texture. Eighty dentin porcelain (ShoFu Vintage Halo, shade A2) disks (1.0 × 10.0 mm) were fabricated and assigned to 10 groups (n=8). The dentin porcelain specimens were given different surface textures with modified surface roughnesses (Ra) and different levels of waviness (Wa). Measurements of transmittance, reflectance, and CIE L*a*b* values were made with a spectrocolorimeter (PR-650) after standard finishing of the enamel-dentin porcelain complex. Translucency parameters (TP) and color difference (ΔE) were calculated with CIE L*a*b* values, respectively. The data were statistically analyzed by 1-way ANOVA and Fisher's LSD (least significant difference) post hoc tests (α=.05). Transmittance, reflectance, and the translucency parameter were influenced significantly by surface roughness (P<.05) and waviness values (P<.01). With a decrease in the Ra value from 1.23 μm to 0.15 μm, mean reflectance values increased from 37.01% to 38.63%, while mean values of transmittance and the translucency parameter decreased from 1.04% to 0.87% and 19.44 to 18.03, respectively. With an increase of the Wa value from 0.0 mm to 0.2 mm, mean values of reflectance decreased from 37.06% to 30.30%, while transmittance and the translucency parameter increased from 1.10% to 2.05% and 19.15 to 20.01, respectively. Color difference values (ΔE) ranged from 0.30 to 1.45 (Ra group) and from 1.46 to 4.16 (Wa group), respectively. Surface texture of dentin porcelain significantly influenced the optical properties of enamel-dentin porcelain specimens, and surface waviness (Wa) had higher correlation coefficients with optical parameters than did roughness (Ra).

Evaluation of Women Farmers’ Perception of the Impact of Women-in-Agriculture Programme on Yield, Income and Decision-making Power in Southeastern Nigeria

One of the reasons that necessitated the establishment of Women-in-Agriculture (WIA) Programme in 1989 was the perception that women farmers were not having adequate access to extension services compared to their male counterparts. Feminists argued that the inadequate access to extension services resulted in women farmers having poor farm yields, income, and decision-making power on what to produce. With the institutionalization of WIA programme since 1989, the study was conducted to evaluate the impact of the programme on women farmers’ yield, income and decision-making power. Multi-stage sampling technique was adopted for sample selection while semi-structured questionnaires were used for data collection. Data collected from 225 contact women farmers were analyzed using Analysis of Variance (ANOVA) and tested at 5% level. Mean separation was equally done with Fisher Least Significant Difference (FLSD). Generally, the grand mean perceptional value (4.21) indicated that women farmers perceived positive changes in their farm yields, income and decision-making power because of the influence of WIA Programme. Analysis of Variance on pooled data indicated that women farmers perceived significant differences (P < 0 .05) in the changes in yield, income and decision-making power. The result, as well, showed that women farmers in the different State’s agricultural zones in Southeastern Nigeria perceived significant differences (P < 0.05) in the changes in yield, income and decision-making power. Mean separation results showed that women farmers perceived the impact more on yield with perceptual mean value of 4.38a. It also revealed that women farmers in Oji agricultural zone in Enugu State had the highest impact in the Southeastern Nigeria with mean perceptional value of 4.61a. Based on the results, the paper strongly recommended that the implementers of the programme should be highly motivated in order to guarantee the sustainability of the programme for agricultural development. Key words: contact women farmers, income, yield, decision-making power, WIA ,

Verification of In Situ Thresholds and Integrated Real-Ear Measurements

Accurate prescriptive gain results in a more accurate fit, lower return rate in hearing aids, and increased patient satisfaction. In situ threshold measurements can be used to determine required gain. The Widex Corporation uses an in situ threshold measurement strategy, called the Sensogram. Real-ear measurements determine if prescriptive gain targets have been achieved. Starkey Laboratories introduced an integrated real-ear measurement system in their hearing aids. To determine whether the responses obtained using the Widex Sensogram were equivalent to those obtained using current clinical threshold measurement methods. To determine the accuracy of the Starkey IREMS™ (Integrated Real Ear Measurement System) in measuring RECD (real-ear to coupler difference) values compared to a dedicated real-ear measurement system. A verification design was employed by comparing participant data measured from standard, benchmark equipment and procedures against new techniques offered by hearing-aid manufacturers. A total of 20 participants participated in this study. Ten participants with sensorineural hearing loss were recruited from the Ohio University Hearing, Speech, and Language Clinic participated in the first experiment. Ten participants with normal hearing were recruited from the student population at Ohio University participated in both experiments. The normal-hearing group had thresholds of 15 dB HL or better at the octave frequencies of 250-8000 Hz. The hearing-impaired group had thresholds of varying degrees and configurations with thresholds equal to or poorer than 25 dB HL three-frequency pure-tone average. The order of measurement method for both experiments was counterbalanced. In Experiment 1, thresholds obtained via the Widex Sensogram were compared to thresholds obtained for each participant using a clinical audiometer and ER-3A insert ear phones. In Experiment 2, RECD values obtained via the Starkey IREMS were compared to RECD values obtained via the Audioscan Verifit™. A repeated-measures analysis of variance (ANOVA) was used for statistical analysis, and a Fisher's LSD (least significant difference) was used as a post hoc analysis tool. A significant difference between Sensogram thresholds and conventional audiometric thresholds was found with the Sensogram method resulting in better threshold values at 0.5, 1.0, and 2.0 kHz for both groups. In Experiment 2, a significant difference between RECD values obtained by the Starkey IREMS and the Audioscan Verifit system was found with significant differences in RECD values found at 0.25, 0.5, 0.75, 1.5, 2.0, and 6.0 kHz. The Sensogram data differ significantly from traditional audiometry at several frequencies important for speech intelligibility. Real-ear measures are still required for verification of prescribed gain, however, calling into question any claims of shortened fitting time. The Starkey IREMS does perform real-ear measurements that vary significantly from benchmark equipment. These technologies represent a positive direction in prescribing accurate gain during hearing-aid fittings, but a stand-alone system is still the preferred method for real-ear measurements in hearing-aid fittings.

Relationship between atmospheric corrections and training-site strategy with respect to accuracy of greenhouse detection process from very high resolution imagery

Frequently, satellite images that are acquired to extract a target surface are atmospherically corrected prior to the detection process. Thus, the unification of measure units is achieved, and atmospheric effects are removed from various imagery sources or taken at different dates. In this paper, four increasing levels of atmospheric corrections are applied (Top-Of-Atmosphere transformation: TOA; Apparent Reflectance Model: ARM; Flat Areas Model: FAM; Non-Flat Areas Model: NFAM). Then, the classification process is carried out using two strategies of training-site definitions (statistically purified and crude training sites) and two satellite imagery sources (QuickBird and Ikonos). Three-way Analysis of Variance (ANOVA) tests and Fisher's least-significant difference tests are included in quality classification assessment, based on four accuracy indexes. Two images from both remote sensors are orthorectified, and then it is checked that all selected atmospheric correction levels have significantly different influences on the statistics of both orthoimages. Taking into account the conditions established in this work, it is concluded that a lower atmospheric correction level would be preferred because it does not present significantly worse results than other levels considered. Training sites would not be statistically purified, and QuickBird or Ikonos would be chosen, depending on the aspect of the greenhouse detection accuracy preferred.

Studies on Meloidogyne javanica infestation on roma tomato (Lycopersicon esculentum Mill) under different soil amendments

The effect of different soil amendments on infestation of Meloidogyne javanica on roma tomato (Lycopersicon esculentum) was investigated at the Federal College of Agriculture, Ishiagu, Nigeria using pot experiment. Completely randomized design was used for experiment and data collected were subjected to analysis of variance (ANOVA). All significant differences observed were separated using Fisher's least significant difference (F-LSD). The parameters measured were plant height (cm) at 50% flowering, number of leaves at 50% flowering, number of fruits per plant at harvest, weight (g) of fresh fruit at harvest, number of galled roots per plant and number of galls per root per plant. The study revealed that there exist significant (P 0.05) effect on weight of fresh fruit at harvest and number of galled roots per plant. Results further showed that soil amended with organic materials (poultry droppings, grass ash and Rice husk ash) at the range of 10 to 20 t/ha were good for optimum growth, performance and control of root-knot nematode of tomato. Therefore, farmers are advised to use 20 t/ha for optimum growth and control of root knot nematode on roma tomato.

Occupational risks factors identified and interventions suggested by welders and computer numeric control workers to control low back disorders in two steel companies

Work-related low back disorders (WLBD) are common and expensive. This study assessed perceived workload and identified issues and possible improvements to reduce WLBD in 64 welders and 44 computer numeric control workers (CNC workers). Injury records were reviewed and a questionnaire was completed. Discomfort ratings and visual analogue scales were compared using one-way ANOVA with Fisher's least-significant difference post hoc test. The annual incidence of recorded WLBD was lower for welders (3.4%) than for CNC workers (5.4%). On the other hand, the working-life incidences of reported WLBD and the point prevalences of low back pain were higher for the welders (55% and 27%, respectively) than for the CNC workers (36% and 16%). The discomfort scores for the low back region were higher than the scores for the other body parts. The weight manually handled [mean (S.D.)] by the welders [21 (6) kg] was lower than by the CNC workers [35 (11) kg]. Perceived exertion was strong for both groups [5 (1)]. For the welders, the postures, repetitions, and duration contributed more to the total effort than the movements and forces ( p<0.035). For CNC workers, repetitions and duration contributed more to the total effort than postures, movements, and force ( p<0.044). The workers identified relevant problems and possible improvements for their jobs. Recommended improvements included adjustable tables, stretching, and crane use by welders, and training, standing mats, clear limits, stable magnets, and less asymmetrical lifting by CNC workers. Précis This study evaluated reported occupational risk factors for WLBD among welders and CNC workers from two steel companies. A questionnaire was responded by 108 steel workers. The information presented can be used to design participatory ergonomic interventions aimed at reducing WLBD.

A note on the power of Fisher's least significant difference procedure

Fisher's least significant difference (LSD) procedure is a two-step testing procedure for pairwise comparisons of several treatment groups. In the first step of the procedure, a global test is performed for the null hypothesis that the expected means of all treatment groups under study are equal. If this global null hypothesis can be rejected at the pre-specified level of significance, then in the second step of the procedure, one is permitted in principle to perform all pairwise comparisons at the same level of significance (although in practice, not all of them may be of primary interest). Fisher's LSD procedure is known to preserve the experimentwise type I error rate at the nominal level of significance, if (and only if) the number of treatment groups is three. The procedure may therefore be applied to phase III clinical trials comparing two doses of an active treatment against placebo in the confirmatory sense (while in this case, no confirmatory comparison has to be performed between the two active treatment groups). The power properties of this approach are examined in the present paper. It is shown that the power of the first step global test--and therefore the power of the overall procedure--may be relevantly lower than the power of the pairwise comparison between the more-favourable active dose group and placebo. Achieving a certain overall power for this comparison with Fisher's LSD procedure--irrespective of the effect size at the less-favourable dose group--may require slightly larger treatment groups than sizing the study with respect to the simple Bonferroni alpha adjustment. Therefore if Fisher's LSD procedure is used to avoid an alpha adjustment for phase III clinical trials, the potential loss of power due to the first-step global test should be considered at the planning stage.

Monitoring a Three-Armed Clinical Trial with Survival Endpoints: Fisher's Least Significant Difference Approach

Researchers have long recognized the importance of monitoring trials to determine whether to terminate a trial early or change a trial because of a substantial treatment effect. Fisher's least significant difference (LSD) procedure has been suggested by Proschan et al. [Proschan, M. A., Follmann, D. A., Geller, N. L. (1994). Monitoring multi-armed trials. Stat. Med. 13:1441–1452] to control the overall type I error rate for trials with three or more arms and survival endpoints. In this paper we propose an alternative Fisher's LSD interim monitoring procedure that uses the same adjusted significance levels for the pairwise tests as for the global test; it continues performing a global hypothesis test at looks subsequent to a look where a global null hypothesis was rejected. We also examine revised Proschan et al. approach that uses the O'Brien–Fleming two-armed trial boundaries for pairwise tests. A simulation study shows that compared to the approach proposed by Proschan et al., the procedure we propose is more powerful and produces overall type I error rates closer to the nominal values when all groups are truly equivalent. For the scenarios examined, the overall type I error rates and power of the proposed approach are virtually equivalent to those of the revised Proschan et al. approach.

A Comparison of the Level of Dyspnea vs Disease Severity in Indicating the Health-Related Quality of Life of Patients With COPD

To compare categorizations of the level of dyspnea with the staging of disease severity as defined by the FEV(1) in representing how the health-related quality of life (HRQOL) is distributed in patients with COPD. Cross-sectional study. Outpatient clinic at the respiratory department of a university hospital. A total of 194 consecutive male patients with stable, mild-to-severe COPD. The score distributions for the components of the St. George's respiratory questionnaire (SGRQ) were used as disease-specific HRQOL measures, and the scores from the Medical Outcomes Study Short Form 36-item questionnaire (SF-36) were used as generic HRQOL measures. These scores were stratified according to the level of dyspnea, as defined by the Medical Research Council (MRC) dyspnea scale, and the stage of disease severity, as defined by the American Thoracic Society (ATS). Differences in the HRQOL scores among the subgroups were compared by an analysis of variance (ANOVA). Multiple pairwise comparisons were made with Fisher's least significant difference (LSD) method, with the overall alpha-level set at 0.05. In those groups classified according to the level of dyspnea, significant differences were observed for the scores on the SGRQ and SF-36 (ANOVA, p < 0.05). The scores for activity and impact, and the total scores of the SGRQ and all scales, except for bodily pain and general health on the SF-36, were significantly worse for patients with severe dyspnea (MRC scale grades, 3, 4, and 5, respectively) than for those with moderate dyspnea (MRC grade level, 2; Fisher's LSD method, p < 0.05). Significant differences were recognized among the different stages of disease severity with respect to the scores from all scales of the SF-36, except for bodily pain, and all scores from the SGRQ (ANOVA, p < 0.05). However, differences in the scores on the SGRQ and SF-36 between patients with ATS stage II disease (FEV(1), 35 to 49% predicted) and stage III disease (FEV(1), < 35% predicted) were not statistically significant. Using the SGRQ and SF-36, the HRQOL of patients with COPD was more clearly separated by the level of dyspnea than by the ATS disease staging. In addition to the ATS disease staging, categorizations based on the level of dyspnea may be useful to clinicians in terms of the HRQOL of COPD patients.

The Paired Comparisons Method of Identifying Developmental Discrepancies with the ITPA

This paper attempts to offer a realistic and viable statistical procedure (paired comparisons or PC method) of identifying potential learning disabilities via the ITPA battery. Such a procedure is predicated on a variation of R.A. Fisher's least-significant difference method, which employs multiple pairwise comparisons, and the PC method attempts to be more sensitive than the methodology proposed by Kirk and Elkins, which employs the absolute average deviation as the critical parameter. Essentially, the PC method used a probabilistic model to ascertain learning discrepancies.

Bayes Least Significant Difference: A Review and Comparison1

AbstractThe Bayesian approach to mean separation overcomes the objections to previous least significant difference (LSD) procedures by having a direct dependence upon the calculated F value. This procedure has the power of a comparisonwise approach when F is moderate to large in size and is conservative at F values less than about 3.0. The Bayes LSD has the same form as the Fisher LSD, i.e., LSD = sdt, where the Bayes t is not to be confused with Student's t. In the example cited, the Bayes LSD was found to be a more powerful test than the Fisher LSD, Tukey's honest significant difference (HSD), or the Duncan new multiple range (DMR) when F = 45.36, moderate in size and comparative to the Fisher LSD and the DMR when F = 4.43, and conservative and comparable to Tukey's HSD when F = 1.4. The use of BLSD rather than LSD to designate the Bayes Least Significant Difference procedure is suggested.