MSA: The forgotten index for identifying inappropriate items before computing exploratory item factor analysis

Kaiser’s single-variable measure of sampling adequacy (MSA) is a very useful index for debugging inappropriate items before a factor analysis (FA) solution is fitted to an item-pool dataset for item selection purposes. For reasons discussed in the article, however, MSA is hardly used nowadays in this context. In our view, this is unfortunate. In the present proposal, we first discuss the foundation and rationale of MSA from a ‘modern’ FA view, as well as its usefulness in the item selection process. Second, we embed the index within a robust approach and propose improvements in the preliminary item selection process. Third, we implement the proposal in different statistical programs. Finally, we illustrate its use and advantages with an empirical example in personality measurement.

A framework to assess the impact of number of trials on the amplitude of motor evoked potentials

The amplitude of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) is a common yet highly variable measure of corticospinal excitability. The tradeoff between maximizing the number of trials and minimizing experimental time remains a hurdle. It is therefore important to establish how many trials should be used. The aim of this study is not to provide rule-of-thumb answers that may be valid only in specific experimental conditions, but to offer a more general framework to inform the decision about how many trials to use under different experimental conditions. Specifically, we present a set of equations that show how the number of trials affects single-subject MEP amplitude, population MEP amplitude, hypothesis testing and test–retest reliability, depending on the variability within and between subjects. The equations are derived analytically, validated with Monte Carlo simulations, and representatively applied to experimental data. Our findings show that the minimum number of trials for estimating single-subject MEP amplitude largely depends on the experimental conditions and on the error considered acceptable by the experimenter. Conversely, estimating population MEP amplitude and hypothesis testing are markedly more dependent on the number of subjects than on the number of trials. These tools and results help to clarify the impact of the number of trials in the design and reproducibility of past and future experiments.

The Within-Subjects Effects of Practice on Performance of Drop Landing in Healthy, Young Adults

Most studies of high-speed lower body movements include practice repetitions for facilitating consistency between the trials. We investigated whether 20 repetitions of drop landing (from a 30.5-cm platform onto a force plate) could improve consistency in maximum ground reaction force, linear lower body stiffness, depth of landing, and jump height in 20 healthy, young adults. Coefficient of variation was the construct for variability used to compare the first to the last five repetitions for each variable. We found that the practice had the greatest effect on maximum ground reaction force (p = .017), and had smaller and similar effects on lower body stiffness and depth of landing (p values = .074 and .044, respectively), and no measurable effect on jump height. These findings suggest that the effect of practice on drop landing differs depending upon the variable measure and that 20 repetitions significantly improve consistency in ground reaction force.

Investigating effects of criterial consistency, the diversity dimension, and threshold variation in formulaic language research

O’Donnell et al. (2013) considered four measures of formulaicity and reported that they produced different results concerning the effects of expertise and first/second language status on formulaic sequence usage in academic writing. The current study explores several additional methodological issues using the same dataset from O’Donnell et al. (2013). We first motivate the need for criterial consistency and investigate whether frequency- and association-based measures yield different results when they are both obtained using corpus-internal criteria. The informativeness of the diversity dimension of formulaic sequence use is then gauged by comparing the results of phrase-frame type-token ratio against those of other measures. Finally, we profile formulaic sequence distribution across quartiles of different measures to assess the effect of variable measure thresholds. Our findings highlight the criticality of issues of criterial consistency, formulaic sequence diversity, and threshold variation in formulaic language research.

PENGARUH PENGGANTIAN DEDAK HALUS DENGAN KULIT KOPI TERHADAP PERSENTASE KARKAS DAN LEMAK ABDOMEN BROILER

THE EFFECTS OF SUBSTITUTION OF RICE BRAIN WITH COFFEE PULP ON BROILER’S CARCASS AND ABDOMINAL LIPID PERCENTAGES. A research evaluating the effects of substitution of rice brain with coffee pulp on broiler’s carcass and abdominal lipid percentage has been conducted at Faculty of Animal Science. Sixty unsexed broiler’s strain Hubbard were used in this experiment. The chicks were allocated into 20 units of cages. A Completely Randomized Design (CRD) was used with 4 treatments and 5 replications. The treatments were R0 (0% coffee pulp), R1 (7% coffee pulp), R2 (14% coffee pulp) and R3 (21% coffee pulp). Variable measure were : carcass percentage and abdominal lipid percentage. Anova showed that there were higly significant effects of treatment on carcass and abdominal lipid percentages. Honestly Significant Difference (HSD) test showed that there were no significant difference on carcass percentage among R0 (72.77%), R1 (71.96%), and R2 (71.45%), however percentage carcass of R3 (67.41%) significantly lower compared to R0, R1, and R2. There were no significant difference abdominal lipid percentage of R0 (1.78%) and R1 (1.70%). R0 and R1 were significantly higher compared to R2 (1.15%) and R3 (0.88%), however R2 was significantly higher compared to R3. It is concluded that the substitution of rice brain with 14% coffee pulp was the best effects on carcass and abdominal lipids of broiler. Keyword : coffee pulp, broiler, carcass percentages, abdominal lipid.

The Measurement of Social Age

A simple-variable measure of social age was developed by regressing chronological age on a number of social correlates of age. The correlates tapped life styles relating to family, work and retirement. The estimated age, in units of years, was taken as the social age. This composite measure was calculated for subjects of the VA Normative Aging Study from a ten-variable equation. “Old” social age was indicated by a greater degree of settling in to one's job, more staving off of retirement, less likelihood of moving and contacts with relatives and greater likelihood of wife's employment than is true of one's age peers. The measure is useful for interdisciplinary analysis with other “ages” similarly derived, such as psychological age, biochemistry age and auditory age, as well as for social gerontologic analysis of subpopulations defined on the basis of age-invariant criteria such as social class and stress experience.

Observing the Classroom Behavior of Elementary School Children

In this study of 10 normal children and a group of children with conduct or acting out disorders, evidence has been presented to suggest that a method of direct behavioral observation in the classroom is reliable, can discriminate between normal and emotionally disturbed children, yields meaningful information on the nature of a child's maladjustment to school when it is of the conduct problem type, offers data on the efficacy of a special class program, serves as a sensitive dependent variable measure of various acute therapeutic manipulations, and is comprised largely of independent items. The relevance of this measure to children with problems other than the conduct problem type has not been established.