Discriminatory Power Index Research Articles

Cultural Adaptation and Psychometric Properties of the Spanish Version of the Gay Affirmative Practice Scale (GAP-ES).

Lesbian, gay, bisexual, and transgender (LGBT) individuals often face discrimination in healthcare settings, resulting in health disparities. Evaluating healthcare professionals' affirmative practices is essential for promoting inclusive care and addressing these disparities. The aim of this study was to assess the psychometric properties of the Spanish version of the Gay Affirmative Practice Scale (GAP-ES), which measures healthcare professionals' affirmative practices towards gay individuals. Before assessing its psychometric properties, the original Gay Affirmative Practice Scale (GAP) was translated and culturally adapted from English to Spanish. Following the translation, the psychometric properties were tested on a sample of 236 healthcare professionals. The internal consistency of the questionnaire was measured using Cronbach's alpha and the discriminatory power index. Factor structure was evaluated with Confirmatory Factor Analysis (CFA) using the Diagonally Weighted Least Squares method. The sample consisted of 152 female (64.41%) and 84 male (35.59%) participants, with 58.05% identifying as heterosexual, 28.81% as homosexual, and 13.14% as bisexual. The internal consistency of the GAP-ES was strong, with Cronbach's alpha values of 0.915 for the Beliefs subscale and 0.902 for the Behaviors subscale. The McDonald's Omega coefficient was 0.942, indicating high reliability. CFA confirmed a two-factor structure with satisfactory fit indices (CFI = 0.999, RMSEA = 0.071). The GAP-ES demonstrates strong internal consistency and a stable factor structure. It is a reliable tool for evaluating affirmative practices toward LGBT patients in Spanish-speaking healthcare contexts, supporting improved care for this population. The integration of the GAP-ES into clinical practice and training programs may support the enhancement of cultural competence among healthcare professionals, contributing to the reduction of health disparities for LGBT patients in Spanish-speaking settings.

Psychometric properties and cultural adaptation of the Polish Version of the Gay Affirmative Practice Scale.

The lesbian, gay, bisexual, and transgender (LGBT) people often face unique medical disparities, including obstacles to accessing adequate and respectful care. The purpose of this study was to test the psychometric properties(internal consistency, reliability, and factor structure) of the Polish-language version of the Gay Affirmative Practice Scale (GAP-PL). The study was conducted over a 6-month period in 2023, from February to June, involving 329 medical students and professionals who evaluated the GAP-PL. Before testing the psychometric properties of the original Gay Affirmative Practice Scale (GAP), it was translated and adapted from the original English language version into the Polish language. Authors then tested the psychometric properties of the tool on a sample of 329 participants. The internal coherence of the questionnaire was tested with the analysis of verifying factors (Confirmatory Factor Analysis). Cronbach alpha and the discriminatory power index were used as internal consistency measures. There were more female than male participants (55.32%). More than 53% of the participants were heterosexual, and the average age of the respondents was ~30 years. The internal consistency of the Polish-language version and its domains was strong with the overall Cronbach's alpha ranges for each subscale domains ranging between 0.936 and 0.949. The McDonald's omega coefficient was 0.963. The GAP-PL has excellent properties of factorial validity and can be used in research and clinical practice in Polish-speaking populations.

Analysis of Microsatellite Length Polymorphism for Clinical Isolates of Candida albicans from Animals

Background: Candida albicans has been shown as the most common species of Candida collected from different animals. Objectives: This study aimed to evaluate the genetic diversity and genetic relationships among C. albicans isolates collected from clinical specimens of animals suffering from candidiasis using microsatellite length polymorphism (MLP). Methods: We used MLP for a group of 60 C. albicans strains isolated from various animal species (dog: 16, cat: 10, horse: 10, cow: 14, chicken: 10), previously defined as animal clinical isolates. Three loci, including EF3, CDC3, and HIS3, were amplified, and the products ran onto an ABI XL 370 genetic analyzer, and fragment sizes were determined. Results: Of the 60 clinical strains illustrated, 49 different genotypes were identified with a discriminatory power index of 0.991. A total of 17 alleles and 26 different combinations were identified for EF3 locus, six alleles and 13 combinations for CDC3 locus, and 17 alleles and 27 combinations for HIS3 locus. The most common genotypes were GP9 (four strains) and GP1 and GP33 (three strains). Wright’s fixation index (FST) values were calculated to assess inter-group genetic diversity for all pairwise combinations of the five sub-populations of C. albicans isolated from the different animal hosts. The highest FST values related to C. albicans isolated from chicken to three sub-populations of cats (FST: 0.1397), cows (FST: 0.0639), and horses (FST: 0.0585). Conclusions: The results indicated a moderate genetic differentiation (0.05 < FST < 0.15) between C. albicans strains isolated from cats, cows, and horses as a mammal vs. chickens.

Effect Size of Mathematics Blended Learning Design on Increasing Mathematical Problem-Solving Ability of Polytechnic Students in the Covid-19 Pandemic Period

The purpose of this study was to determine the effect size of the blended learning design on increasing the Mathematical Problem-Solving Ability of polytechnic education students during the covid 19 pandemic. The study was carried out at the Bali State Polytechnic (BSP), using a mastery-experimental approach, with a pre-test post-test design of non-equivalent control. design groups. The subjects are students in the engineering field of BSP in 2020/2021. Samples were taken purposively as many as 10 classes and divided into experimental and control groups. Data were collected using a mathematical ability test developed by the researcher. The level of validity is between 0.31 and 0.89, the reliability is 0.97, the average difficulty level is 0.41 and the discriminatory power index is between 0.25 to 0.75. Data were analyzed using t test, paired t test and N-Gain score. There is a significant difference between the average mathematical problem solving ability of students taught using the blended learning model and being taught using the full e-learning model. The blended learning model is more effective in improving mathematical problem solving abilities than the full e learning model. The effect size is very large on increasing mathematical solving abilities in learning using blended learning. The implication is that the optimal application of the blended learning design in polytechnic education during the covid 19 pandemic, the learning process becomes more effective and succeeds in improving students' mathematical problem solving abilities.

High rate of reinfection and possible transmission of Mycobacterium avium complex in Northeast Thailand

The Mycobacterium avium complex (MAC) includes two main species of non-tuberculous mycobacteria (NTM), M. avium and Mycobacterium intracellulare. These can cause serious disease, especially in immunocompromised patients. Little information is available concerning genetic diversity of NTM. We used multilocus sequence typing (MLST) based on a highly discriminative gene set to analyze MAC serially isolated from patients to determine the rate of MAC reinfection. Genomic DNA was sequenced from 49 MAC isolates (15 cases comprised of 11 true infections and 4 instances of colonization). More than half of the MAC isolates tested were found to be multidrug resistant. The discriminatory power was assessed of 24 house-keeping genes (fusA, atpD, pheT, glnA, topA, secA, argH, glpK, murC, cya, pta, rrl, rrs, hsp65, rpoB, 16S-23S rRNA ITS, recF, lipT, pepB, gnd, aspB, groEL, sodA and est) previously used for genotyping of MAC and other NTM. Seven genes (fusA, secA, rpoB, hsp65, 16S rRNA, 23S rRNA, 16S-23S rRNA ITS) had a discriminatory power index higher than 0.9 and were included in the optimized set that we used. This set was significantly better for genotyping and diagnosis of MAC than previously used 4-gene, 5-gene and 9-gene sets. MLST using our 7-gene set indicated that the rate of reinfection was 54.55% (6/11 cases). Persistent infections (n = 5 cases, 45.45%) were found. A changing of clone in the same patient was found in 1/4 (25%) of the colonization cases. Two small clusters of possible MAC transmission between humans were found. Our study demonstrated that the high frequency of apparent treatment failure of MAC might be artefactual, as a consequence of a high rate of MAC reinfection in Thai population. Our useful highly discriminative gene set for MAC species and clonal strain analysis could be further applied for the diagnosis and patient management.

The Development Of Character Achievement Test For Islamic University Students

This study aims to develop an instrument that has never been created before, the statistically good character test. The instrument can be used to measure the character of Muslim students at the level of competence in knowledge, comprehension, and application. The test development applies a modified 4D model procedure into three stages, define, design, and develop. The reliability of the test was obtained based on the level of reliability, the level of difficulty of the questions, the discriminatory power, and the effectiveness of alternative distractors. The research was conducted in 2021 with a total of 50 students. The results of the study (1) reliability coefficient (α) 0.938, (2) the average item difficulty level (p) 0.643, (3) the average discriminatory power index (rpbis) was 0.522, (4) the alternative distractors were categorized as effective (50%) and ineffective (50%). Based on these findings, it shows that cognitive test devices are feasible to use and can be used to determine the character of Muslim students.

Genomic polymorphism of Trifolium repens root nodule symbionts from heavy metal-abundant 100-year-old waste heap in southern Poland

In total, 77 rhizobial strains isolated from the root nodules of T. repens, inhabiting heavy metal-contaminated waste heap (36 isolates) and control grassland (41 ones) in southern Poland, were analyzed for genome polymorphism and strength of the heavy metals’ (mainly Zn, Pb, Cd) selective pressure on bacterial genome polymorphism using two PCR-based techniques, ERIC- (enterobacterial repetitive intergenic consensus) and REP-PCR (repetitive extragenic palindromic) sequences. Both methods of different discriminatory power index (D) (ERIC-PCR D = 0.9737; REP-PCR D = 0.9826) allowed to distinguish 47 and 44 rhizobial strains, respectively. Combined analysis of ERIC-PCR and REP-PCR DNA amplicons differentiated all tested isolates. Both ERIC- and REP-PCR DNA fingerprinting techniques showed significant decline of the genome polymorphism (h) in rhizobial population from metalliferous waste heap (h = 0.89 ± 0.03; h = 0.90 ± 0.02, respectively) compared to rhizobia from control non-metalliferous area (h = 0.99 ± 0.01; h = 0.98 ± 0.02, respectively) as well as substantial differences in the genomic polymorphism between both these populations (FST = 0.162, p = 0.008; FST = 0.170, p = 0.000, respectively).

Characterization and CRISPR-based genotyping of clinical trh-positive Vibrio parahaemolyticus

BackgroundVibrio parahaemolyticus is a causative agent of gastroenteritis. Most of the clinical isolates carry either tdh and/or trh genes which are considered as the major virulence genes of this pathogen. In this study, the clinical isolates of V. parahaemolyticus carrying trh gene (n = 73) obtained from 1886 to 2012 from various countries were investigated for the urease production, haemolytic activity, and biofilm formation. In addition, the potential of clustered regularly interspaced short palindromic repeats (CRISPR)-based genotyping among these isolates was investigated.ResultsIn this study, no significant differences were observed in the urease production between tdh+trh1+ and tdh+trh2+ isolates (p = 0.063) and between the tdh−trh1+ and tdh−trh2+ isolates (p = 0.788). The isolates carrying only the trh gene showed variation in their haemolytic activity. The ratio of urease production and haemolytic activity between the trh1+ and trh2+ isolates and biofilm formation of trh+V. parahaemolyticus isolates were not significantly different. Sixteen of thirty-four tested isolates (47.0%) of trh+V. parahaemolyticus were positive for CRISPR detection. The discriminatory power index (DI) of CRISPR-virulence typing was higher than the DI obtained by CRISPR typing alone.ConclusionThe tdh and trh genes were not involved in urease production in the trh+V. parahaemolyticus, and variation of haemolytic activity detected in V. parahaemolyticus carrying only the trh gene might be correlated to the sequence variation within trh1 and trh2 genes. Additionally, biofilm production of V. parahaemolyticus was not associated with harboring of virulence genes. For genotyping, CRISPR sequences combined with virulence genes can be used as genetic markers to differentiate trh+V. parahaemolyticus strains.

Microsatellite Length Polymorphism for DNA-Based Typing of Candida albicans Isolated from HIV Positive Patients in Tehran, Iran

Background: The importance of Candida albicans as the most common cause of fungal infections in humans is undeniable. Genotyping methods have been developed as useful tools to differentiate between fungal strains isolated from various infections. Several molecular typing methods have been described for C. albicans, and fragment length analysis of microsatellites called microsatellite fragment length polymorphism (MLP) is one of the most accurate genotyping methods. Objectives: The present study aimed at evaluating the genetic diversity and genetic relationships among C. albicans isolates recovered from HIV-positive patients with oral candidiasis in Iran using MLP. Methods: We analyzed 30 isolates of C. albicans obtained from HIV-positive patients in Tehran. Genotypes of C. albicans isolates associated with oropharyngeal candidiasis were determined using microsatellite length polymorphism analysis. Three loci including EF3, CDC3, and HIS3 were amplified using multiplex PCR. After amplification, the product was run on an automated single-capillary genetic analyzer, and band sizes (known as alleles) were calculated with gene scan mapper. Results: PCR MLP typing of the 30 isolates under study yielded 27 different profiles, and the discriminatory power index was obtained as 0.993. Ten alleles and 18 different combinations were detected for the EF3 gene, 7 alleles and 18 combinations for the EF3 gene, and 10 alleles and 14 combinations for the HIS3 gene. Only 2 isolates were homozygous in all the 3 loci. To identify the origin of superficial infections in 6 patients, C. albicans isolates from the superficial as well as oral samples were simultaneously genotyped. Results showed the identity of genotypes in 4 of these patients. For 1 patient, the C. albicans genotype of the nails was different from the genotype observed in the oral cavity, which raised the possibility of an exogenous source for the superficial infection. Also, there were changes at only 1 or 2 alleles, which represented microevolution in some isolates. Conclusions: The high variation of genotypes throughout the population of C. albicans suggested that the microsatellite fragment length polymorphism using multiplex PCR-based system provided high-speed genotyping, indicating its usefulness in molecular epidemiological evaluation.

Application of whole genome sequence data in analyzing the molecular epidemiology of Shiga toxin-producing Escherichia coli O157:H7/H-

Seventeen clusters of Shiga toxin-producing Escherichia coli O157:H7/- (O157) strains, determined by cluster analysis of pulsed-field gel electrophoresis patterns, were analyzed using whole genome sequence (WGS) data to investigate this pathogen's molecular epidemiology. The 17 clusters included 136 strains containing strains from nine outbreaks, with each outbreak caused by a single source contaminated with the organism, as shown by epidemiological contact surveys. WGS data of these strains were used to identify single nucleotide polymorphisms (SNPs) by two methods: short read data were directly mapped to a reference genome (mapping derived SNPs) and common SNPs between the mapping derived SNPs and SNPs in assembled data of short read data (common SNPs). Among both SNPs, those that were detected in genes with a gap were excluded to remove ambiguous SNPs from further analysis. The effectiveness of both SNPs was investigated among all the concatenated SNPs that were detected (whole SNP set); SNPs were divided into three categories based on the genes in which they were located (i.e., backbone SNP set, O-island SNP set, and mobile element SNP set); and SNPs in non-coding regions (intergenic region SNP set). When SNPs from strains isolated from the nine single source derived outbreaks were analyzed using an unweighted pair group method with arithmetic mean tree (UPGMA) and a minimum spanning tree (MST), the maximum pair-wise distances of the backbone SNP set of the mapping derived SNPs were significantly smaller than those of the whole and intergenic region SNP set on both UPGMAs and MSTs. This significant difference was also observed when the backbone SNP set of the common SNPs were examined (Steel-Dwass test, P≤0.01). When the maximum pair-wise distances were compared between the mapping derived and common SNPs, significant differences were observed in those of the whole, mobile element, and intergenic region SNP set (Wilcoxon signed rank test, P≤0.01). When all the strains included in one complex on an MST or one cluster on a UPGMA were designated as the same genotype, the values of the Hunter-Gaston Discriminatory Power Index for the backbone SNP set of the mapping derived and common SNPs were higher than those of other SNP sets. In contrast, the mobile element SNP set could not robustly subdivide lineage I strains of tested O157 strains using both the mapping derived and common SNPs. These results suggested that the backbone SNP set were the most effective for analysis of WGS data for O157 in enabling an appropriation of its molecular epidemiology.

Genotyping of clinical isolates of Candida glabrata from Iran by multilocus sequence typing and determination of population structure and drug resistance profile.

Candida glabrata is often the second most common causative agent for candidiasis following Candida albicans. Despite the importance of C. glabrata infections, few epidemiological studies have been conducted on this issue. The goal of this study was genotyping of clinical isolates of C. glabrata by multilocus sequence typing (MLST) technique for determination of the endemic prevalent genotypes and any association between isolation source and drug resistance. A total of 50 C. glabrata clinical isolates from Iran were analyzed by MLST and tested for in-vitro susceptibilities to amphotericin-B, caspofungin, fluconazole, and voriconazole according to the Clinical Laboratory Standards Institute (CLSI) M27-A4 document guidelines. Among these isolates, 16 distinct STs were identified, indicating a discriminatory power index of 0.9029. The three major sequence types (STs) were ST-59, ST-74, and ST-7 with 10, 8, and 7 isolates, respectively. Furthermore, a total of 11 new sequences were found, to which no allele numbers were assigned in the MLST database. All the isolates were susceptible to amphotericin B and caspofungin. Fluconazole resistance was shown in four isolates. Also, a sole isolate was voriconazole resistant. This study shows that the population structure of C. glabrata in Iran consists of groups closely related to the global database as well as to some new clonal clusters and STs. Regarding the high prevalence of 11 new sequences found in this study, it can be concluded that, these new alleles are among the endemic genotypes of Iran. The genotypes or STs were independent of drug susceptibility and anatomic sources.

Microsatellite typing identifies the major clades of the human pathogen Candida albicans

Candida albicans population studies showed that this species could be divided into sub-groups of closely related strains, designated by clades. Since the emergence of microsatellite analysis as a PCR based method, this technique has been successfully used as a tool to differentiate C. albicans isolates but has never been tested regarding clustering of the five major clades. In this study we tested microsatellite length polymorphism (MLP) ability to group 29 C. albicans strains previously defined as belonging to clades I, II, III, E and SA, nine atypical strains from Angola and Madagascar, and 78 Portuguese clinical isolates. MLP typing of the total 116 strains analyzed yielded 87 different multilocus allelic combinations which resulted in a high discriminatory power index, of 0.987, with only two markers, CA1 and CEF3. Cluster analysis of the 29 previously defined strains grouped them according to their clade designation with a matrix cophenetic correlation of r = 0.963 after a normalized Mantel statistic. Clustering analysis of the 116 strains maintained the same groupings, clearly defining the five major C. albicans clades. The cophenetic value obtained was of r = 0.839, and the one-tail probability of the normalized Mantel statistic out of 1000 random permutations was P = 0.0020. The proportion of Portuguese isolates in the groups I, II, III and SA was of 2.7%, 15.4%, 3.8% and 0%, respectively. None of the isolates co-clustered with the atypical strains. These results confirm MLP typing as a good method both to type and differentiate C. albicans isolates and to group isolates, identifying the major C. albicans clades, similarly to Ca3 fingerprinting and multilocus sequence typing (MLST).

Utility of Microsatellite Markers and Amplified Fragment Length Polymorphism in the Study of Potentially Ochratoxigenic Black Aspergilli

Microsatellite markers and the results of amplified fragment length polymorphism (AFLP) were compared in the characterization of 68 Aspergillus carbonarius and A. niger aggregate strains of differing ochratoxin-producing ability and from different geographic areas, isolated mainly from grapes and soil. AFLP was applied to both A. carbonarius and A. niger aggregate strains, and it clearly differentiated these species. Microsatellite markers were only applied to A. niger aggregate strains because of the species-specific nature of these markers. Both AFLP and microsatellite marker analyses were able to divide A. niger aggregate strains into the two recognized internal transcribed spacer (ITS)-5.8S rDNA RFLP types, N and T. Clustering of A. niger aggregate strains was similar in both AFLP and microsatellite analyses, yielding an additional separation of N type strains into two groups. Both microsatellite marker and AFLP analyses showed high levels of polymorphism in the A. niger aggregate (index of discriminatory power 0.991 and 1.0, respectively). Of the two techniques, microsatellite marker analysis was quicker and more straightforward to perform. In addition, microsatellite marker analysis is more reproducible, and the results can be expressed as quantitative data, making microsatellite markers a good candidate for use in large-scale studies of genetic diversity in A. niger aggregate species.

Comparison of Microsatellite Length Polymorphism and Multilocus Sequence Typing for DNA-Based Typing of Candida albicans

For genotyping Candida albicans isolates, two PCR-based methods have recently emerged: multilocus sequence typing (MLST), based on the sequence of selected genes, and microsatellite length polymorphism (MLP), based on the length of PCR products containing variable numbers of short DNA repeats. To compare the two methods in their abilities to differentiate and group C. albicans isolates, we selected 50 independent isolates collected at the National Reference Center for Mycoses and Antifungals. MLST typing was performed using sequencing of seven loci as described at (http://test1.mlst.net). The MLP method consisted of a single multiplex PCR testing three different loci. Dendrograms were constructed by the unweighted pair group cluster method with Euclidean metric for both methods. The correlation between the distance matrices was performed with a Mantel test tested with 1,000 random permutations. The sensitivity and specificity of the MLP typing system were determined after allocating MLST groups for the greater number of isolates of each distinct MLP group. The discriminatory power index was >0.99, and the distances between the isolates were highly correlated with both systems. The Mantel coefficient and the Pearson product-moment correlation coefficient were 35,699 and 0.32, respectively (P < or = 1.2 x 10(-6)). Using MLP, the average specificity and sensitivity of clustering compared to MLST were 83% and 73%, respectively, when the singletons were excluded. The two methods are similarly discriminatory and can be interchangeable depending on the objectives. MLP is less expensive and faster than MLST. However, MLST is currently more accurate and additional standardization is needed for MLP.

Molecular markers with potential to replace phage typing for Salmonella enterica serovar typhimurium

Using Amplified Fragment Length Polymorphism (AFLP) analysis of isolates from 23 phage types, we isolated 11 molecular markers that are potentially useful for molecular typing of Salmonella enterica serovar typhimurium. We tested these and 11 previously studied markers for their ability to discriminate among isolates and for correlation of their distribution with phage types. The Simpson's index of discriminatory power for the molecular markers is 0.96. One hundred and twenty one isolates from 33 phage types tested were divided into 51 types which are further grouped into 24 patterns. Eight patterns can unambiguously identify 8 phage types and a further 12 correlated with phage type distribution, showing the usefulness of these markers for molecular phage typing.

Fluorescent amplified-fragment length polymorphism subtyping of the Salmonella enterica serovar enteritidis phage type 4 clone complex.

Fluorescent amplified-fragment length polymorphism (FAFLP) analysis, a high-resolution PCR-based genome fingerprinting method, was used to subtype Salmonella enterica serovar Enteritidis phage type 4. This single phage type is responsible for the majority of salmonellosis in Europe. Twenty strains isolated from nine outbreaks, five isolates from sporadic cases of human infection, four strains of poultry origin, and one laboratory-derived strain were comparatively studied by pulsed-field gel electrophoresis (PFGE) and FAFLP analysis. Following macrorestriction with XbaI, PFGE classified 73% of PT4 strains as a single type. FAFLP analysis was carried out with the primer pair EcoRI+0 and MseI+C, by simultaneously sampling 170 to 190 loci throughout the PT4 genome. Twenty-three FAFLP profiles, with 1 to 61 amplified-fragment differences, were found among the 30 strains. The index of discriminatory power of FAFLP analysis was 0.98, compared to 0.47 for PFGE. FAFLP analysis assigned genotypes to each PT4 outbreak, as well as sporadic PT4 infections, a significant development for the epidemiology and control of this zoonotic enteric pathogen.

Evaluation of a restriction fragment length polymorphism typing method for Listeria monocytogenes

The results of an evaluation of restriction fragment length polymorphism (RFLP) typing for Listeria monocytogenes are presented. The method depends on the use of cloned DNA fragments from an L monocytogenes (serovar 4b) strain to probe Southern blotted NciI restriction fragments derived from L. monocytogenes strains. Analyses of 862 isolates of serogroups 1 2 , 3 and 4 were performed and a total of 32 RFLP patterns were observed. Interstrain RFLPs were common within serogroup 1 2 and the numerical index of discriminatory power for this group was 0.883. Serogroup 4 strains were divided into two major and three minor RFLP types, suggesting a high level of genotypic homogeneity, and the numerical index of discriminatory power was correspondingly low. The technique was found to be highly reproducible, and the stability of patterns was demonstrated by analyses of passaged strains and multiple isolates of the same strain from related specimens. RFLP typing is of value in epidemiological investigations invoking strains of serogroup 1 2 .

ESTIMATION OF REALIZED SIGNAL TO NOISE RATIO FOR A PAIR OF MULTIVARIATE SIGNALS

SummaryConsider the case of classifying an incoming message as one of two known p‐dimension signals or as a pure noise. Let the noise co‐variance matrix (assumed to be same in all the three cases) be unknown. We consider the problem of estimation of “realized signal to noise ratio matrix”, which is an index of discriminatory power, under various loss functions. Optimum estimators are obtained under these loss functions. Finally, an attempt is made to provide a lower confidence bound for the realized signal to noise ratio matrix. In the process, the probability distribution of the smaller eigenvalue of a 2 × 2 confluent hypergeometric random matrix is obtained.

Testing the Validity of the Griffin/Keogh Model For Movement Confidence by Analyzing Self-Report Playground Involvement Decisions of Elementary School Children

Abstract In this study, the interaction of such factors as competence, potential for enjoyment, and potential for harm as postulated in the Model for Movement Confidence was studied by analyzing responses of 250 fifth-grade children in the Omaha Public Schools to a Playground Movement Confidence Inventory (PMCI). The PMCI was designed to assess movement confidence and the bases for performance decisions. Multiple discriminant analyses and analytical cross-validation were used to determine an index of discriminatory power, stability of the instrument, and a validity coefficient for scale classification power. All three model factors were found to influence the confidence of children in performing the playground tasks in the inventory. The PMCI successfully classified 85.16% of total cases representing a .5726 proportional reduction in error over chance. The factor analysis model accounted for 54% of the total variance with 90% of this variance explained by the competency subscale. The enjoyment and harm su...

Multiple discriminant analysis: A BASIC program for microcomputers

The author's mailing address is: School of Psychology, University of Ottawa, 275 Nicholas, Ottawa, Ontario, Canada KIN 6N5. Multiple discriminant analysis (MDA) is a multivariate data-analysis technique that can be used to examine the possibility that a linear combination (discriminant function) of P correlated variables can be used to discriminate K groups of subjects, to test the significance ofdifference between groups centroids, and/or to classify subjects into various groups along the discriminant function. The foundations, as well as the mechanics involved, are described in most textbooks on multivariate analysis (Lindeman, Merenda, & Gold, 1980; Marascuilo & Levin, 1983; Pedhazur, 1982; Tabachnick & Fidell, 1983). The purpose of the program presented here is to perform multiple discriminant analysis, including tests of significance and generation of the classification functions. All critical computations are performed in double precision to minimize rounding errors. The routine to obtain the eigenstructure of the asymmetrical matrix, using the deflation power method, was derived from Douglass's (1983) algorithm. The computational procedure used in the program development was described in Marascuilo and Levin (1983) and in Pedhazur (1982). Input. The program requests the number of variables (NV), the number of groups (K), and the number of subjects within each group (nj). Unequal numbers of subjects per cell are allowed. The raw data can then be entered either sequentially from the keyboard or from a disk file. In the latter case, the data file editor (described earlier, in Coulombe, 1983) can be used to generate a data file suitable as input to this program. The file should contain, first, the total number of scores (NV x Enj) and then the scores themselves, from A1SIV1 to AkSn(k)Vnv, the last index moving fastest (A = group, S = subject, and V = variable). Output. All outputs are directed to the line printer. If screen output is desired, the LPRINT statements should be replaced with PRINT statements. This can be performed easily with the line editor function (EDLIN) provided with MS-DOS. Table 1 is a sample printout obtained using data presented in Lindeman et al. (1980, p. 188). It includes a listing of: (1) the mean and standard deviation vectors observed for each group and variables; (2) the characteristic roots (eigenvalues), index ofdiscriminatory power, Wilks' lambda, R squared, and test of significance (Bartlett's test); (3) the discriminant functions, expressed in both standardized and unstan-