Some comments on selecting the best of several binomial populations or the bivariate normal population having the largest correlation coefficient

Using variance stabilizing transformations, this note describes approximate solutions to the ranking and selection problem of selecting the best binomial population or the bivariate normal population with the largest correlation coefficient.     

On the numerical approximation of the bivariate normal (tetrachoric) correlation coefficient

In this paper a rapid and reliable method is found for estimating the value of the Bivariate Normal Correlation Coefficient, ρ, given values of the joint probability and the normal deviates,h andk, or the related areas. This technique finds useful application in the computational approximation of the tetrachoric correlation coefficient,r, when the underlying distributions may be assumed to be normal.     

Estimation of the correlation coefficient in the case of a bivariate normal population when one of the variables is dichotomized

It is shown that the problem of estimation of the correlation coefficient of a bivariate normal population when one of the variables is dichotomized may be attacked with “probit analysis” methods. This represents an extension of the work of Gillman and Goode (3), as it was possible to find by this approach an approximation to the large-sample variance of the resulting estimateG ofρ. An empirical investigation was undertaken with the object of obtaining some information about the distribution ofG for large sample size. Methods for determining the “pass-fail” cut-off are considered.     

Estimation of other coefficients of correlation from the phi coefficient

Formulas are developed for estimating a point-biserialr or a tetrachoricr from an obtained phi coefficient. The estimate of a tetrachoricr, which is calledr _φ, is shown to be equivalent to that obtained from first-order use of the tetrachoricr series. A tabulation is made of corrections needed to maker _φ equivalent numerically to the tetrachoricr. In spite of its greater generality than estimates of tetrachoricr by previous methods, there are limitations, which are pointed out.     

Estimation of the correlation coefficient in contingency tables with possibly nonmetrical characters

A method of estimating the product moment correlation from the polychoric series is developed. This method is shown to be a generalization of the method which uses the tetrachoric series to obtain the tetrachoric correlation. Although this new method involves more computational labor, it is shown to be superior to older methods for data grouped into a small number of classes.     

Ezekiel’s classic estimator of the population squared multiple correlation coefficient: Monte Carlo-based extensions and refinements

Abstract

Ezekiel’s adjusted R² is widely used in linear regression analysis. The present study examined the statistical properties of Ezekiel’s measure through a series of Monte Carlo simulations. Specifically, we examined the bias and root mean squared error (RMSE) of Ezekiel’s adjusted R² relative to (a) the sample R² statistic, and (b) the sample R² minus the expected value of R². Simulation design factors consisted of sample sizes (N?=?50, 100, 200, 400), number of predictors (2, 3, 4, 5, 6), and population squared multiple correlations (ρ² = 0, .10, .25, .40, .60). Factorially crossing these design factors resulted in 100 simulation conditions. All populations were normal/Gaussian, and for each condition, we drew 10,000 Monte Carlo samples. Regarding systematic variation (bias), results indicated that with few exceptions, Ezekiel’s adjusted R² demonstrated the lowest bias. Regarding unsystematic variation (RMSE), the performance of Ezekiel’s measure was comparable to the other statistics, suggesting that the bias-variance tradeoff is minimal for Ezekiel’s adjusted R². Additional findings indicated that sample size-to-predictor ratios of 66.67 and greater were associated with low bias and that ratios of this magnitude were accompanied by large sample sizes (N?=?200 and 400), thus suggesting that researchers using Ezekiel’s adjusted R² should aim for sample sizes of 200 or greater in order to minimize bias when estimating the population squared multiple correlation coefficient. Overall, these findings indicate that Ezekiel’s adjusted R² has desirable properties and, in addition, these findings bring needed clarity to the statistical literature on Ezekiel’s classic estimator.     

A new rank correlation coefficient with application to the consensus ranking problem

The consensus ranking problem has received much attention in the statistical literature. Given m rankings of n objects the objective is to determine a consensus ranking. The input rankings may contain ties, be incomplete, and may be weighted. Two solution concepts are discussed, the first maximizing the average weighted rank correlation of the solution ranking with the input rankings and the second minimizing the average weighted Kemeny–Snell distance. A new rank correlation coefficient called τ_x is presented which is shown to be the unique rank correlation coefficient which is equivalent to the Kemeny‐Snell distance metric. The new rank correlation coefficient is closely related to Kendall's tau but differs from it in the way ties are handled. It will be demonstrated that Kendall's τ_b is flawed as a measure of agreement between weak orderings and should no longer be used as a rank correlation coefficient. The use of τ_x in the consensus ranking problem provides a more mathematically tractable solution than the Kemeny–Snell distance metric because all the ranking information can be summarized in a single matrix. The methods described in this paper allow analysts to accommodate the fully general consensus ranking problem with weights, ties, and partial inputs. Copyright © 2002 John Wiley & Sons, Ltd.     

Canonical correlation of a temporal lobe signs scale with schizoid and hypomania scales in a normal population: men and women are similar but for different reasons.

The relationships between four relevant Minnesota Multiphasic Personality Inventory variables and temporal lobe signs and symptoms were determined separately for 70 university men and 86 women. Canonical correlations were similar in magnitude (0.55 to 0.60) but indicated sex-specific construction of the roots. For men the significant variables were the schizoid and complex partial epileptic-like signs; for women the significant variables were hypomania and all three temporal lobe clusters: complex partial seizure experiences, interictal-like signs, and religious/psi phenomenology.     

Self-reported psychosocial factors among in vitro fertilization patients interviewed alone or with the partner

The purpose of this study was to compare the sociodemographic and psychosocial characteristics reported by female in vitro fertilization (IVF) patients interviewed alone or with the partner in heterosexual couples. During 12 months (2011–2012), all patients undergoing IVF or intracytoplasmic sperm injection at one public reproductive medicine unit, in Portugal, were interviewed on the day of the diagnosis of pregnancy, being recruited 221 women interviewed with the partner and 92 interviewed alone. Interviewers collected data on sociodemographic and obstetric characteristics; and anxiety, depression, social support and partner relationship were collected by self-administered questionnaires. χ² test was used to assess the independent association between the categorical variables and being interviewed alone or with the partner. For continuous variables, mean or median differences were compared by the t-test or the Mann–Whitney test, according to data distribution. No statistically significant differences were found in the self-reporting of depression, anxiety, social support and partner relationship or in sociodemographic and obstetric characteristics between women interviewed alone or with the partner. Although women interviewed alone were older and more frequently had children than women interviewed with the partner, no significant associations were observed. Thus, having a male partner present in the research setting during a self-administered questionnaire seems not to influence women’s responses to psychosocial measures. Other outcomes and settings need to be evaluated to support evidence-based guidelines for research on infertility.     

Using the PAI with an eating disordered population: scale characteristics,factor structure,and differences among diagnostic groups

Psychometric properties of the Personality Assessment Inventory (PAI; Morey 1991) within an eating disordered sample seeking treatment (N = 238) and differences among eating disorder diagnostic groups on the PAI were examined. The PAI showed acceptable alpha coefficients, item-total correlations, and interitem correlations. The factor structure was similar to that reported by Morey (1991), with the addition of another factor related to interpersonal coolness and distance. Those with binge eating disorder (BED) reported fewer problems and less distress in general compared to other eating disordered groups. The BED and bulimia nervosa groups were different from the anorexia nervosa groups in frequency of matching on two PAI clusters. Use of the PAI with an eating disordered population and its utility in understanding eating disorder diagnostic groups is supported.     

Investigating intellect from a trait activation perspective: Identification of situational moderators for the correlation with work-related criteria

We applied trait activation theory to investigate the situational properties that moderate the correlation of intellect, a sub-dimension of the Big Five factor openness to experience, with work-related criteria. We collected data from a sample of 185 employees from diverse organizations and positions. Results from moderated hierarchical regression analyses revealed that perceived situational properties at the task level moderated the correlation between intellect and job performance. Additionally, correlations between intellect and organizational commitment were moderated at task and organizational levels. This study shows how trait activation theory can be utilized to investigate the situational properties moderating the correlation of personality variables with external criteria. Implications for applied purposes are discussed.     

Facial expressions and the ability to recognize emotions from the eyes or mouth: A comparison among old adults,young adults,and children

The aim of the present study was to contribute to the literature on the ability to recognize anger, happiness, fear, surprise, sadness, disgust, and neutral emotions from facial information (whole face, eye region, mouth region). More specifically, the aim was to investigate older adults' performance in emotions recognition using the same tool used in the previous studies on children and adults’ performance and verify if the pattern of emotions recognition show differences compared with the other two groups. Results showed that happiness is among the easiest emotions to recognize while the disgust is always among the most difficult emotions to recognize for older adults. The findings seem to indicate that is more easily recognizing emotions when pictures represent the whole face; compared with the specific region (eye and mouth regions), older participants seems to recognize more easily emotions when the mouth region is presented. In general, the results of the study did not detect a decay in the ability to recognize emotions from the face, eyes, or mouth. The performance of the old adults is statistically worse than the other two groups in only a few cases: in anger and disgust recognition from the whole face; in anger recognition from the eye region; and in disgust, fear, and neutral emotion recognition from mouth region.     

Living with the unexplained: coping,distress, and depression among women with chronic fatigue syndrome and/or fibromyalgia compared to an autoimmune disorder

Chronic fatigue syndrome (CFS) and fibromyalgia are disabling conditions without objective diagnostic tests, clear-cut treatments, or established etiologies. Those with the disorders are viewed suspiciously, and claims of malingering are common, thus promoting further distress. It was hypothesized in the current study that levels of unsupportive social interactions and the coping styles used among those with CFS/fibromyalgia would be associated with perceived distress and depressive symptoms. Women with CFS/fibromyalgia (n = 39), in fact, reported higher depression scores, greater perceived distress and more frequent unsupportive relationships than healthy women (n = 55), whereas those with a chronic, but medically accepted illness comprising an autoimmune disorder (lupus erythematosus, multiple sclerosis, rheumatoid arthritis; n = 28), displayed intermediate scores. High problem-focused coping was associated with low levels of depression and perceived distress in those with an autoimmune condition. In contrast, although CFS/fibromyalgia was also accompanied by higher depression scores and higher perceived distress, this occurred irrespective of problem-focused coping. It is suggested that because the veracity of ambiguous illnesses is often questioned, this might represent a potent stressor in women with such illnesses, and even coping methods typically thought to be useful in other conditions, are not associated with diminished distress among those with CFS/fibromyalgia.     

The prevalence of symptoms of Post-Traumatic Stress Disorder among soldiers with amputation of a limb or spinal injury: a report from a rehabilitation centre in Sri Lanka

Post-Traumatic Stress Disorder has been identified as one of the most commonly occurring mental illnesses in combatants. This study was conducted to determine the prevalence of Post-Traumatic Stress Disorder among soldiers who had undergone amputation of a lower or an upper limb or sustained a spinal cord injury in the battlefield, and to compare the prevalence among these categories. The research presented seeks to increase the awareness of this condition among those treating war casualties so that appropriate treatment choices could be made to address them. The study was carried out in 2009 at a rehabilitation centre for combatants of war. Data were collected from 96 male army veterans between the ages of 18-49 years using a pre-tested self-administered questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders, the Impact of Event Scale and the PTSD symptom scale. Soldiers with injuries sustained at least four weeks prior to the study were selected by a convenience sampling technique. Soldiers with multiple injuries, head injuries or those diagnosed with psychiatric disorders were excluded. The results revealed that 41.7% of the study population was compatible with the diagnosis of Post-Traumatic Stress Disorder. Within the three groups, 42.5% of the lower limb amputees, 33.3% of the upper limb amputees and 45.7% of the participants with spinal cord injury had symptoms compatible with Post-Traumatic Stress Disorder. There was no difference between the prevalence among the different injury categories considered. This study highlights the need to pay more attention in providing psychological care as a part of the overall health management of injured combatants. Early preparation of soldiers for stressors of war and screening for and proper management of Post-Traumatic Stress Disorder will improve the overall outcome of rehabilitation.     

employment or economic success: the experience of individuals with disabilities in transition from school to work

This research explores the mediating effects of severity of disability on the employment outcomes of participants with disabilities, taking into account their perception of interest‐job match. Participants were 115 high school students with disabilities who took part in an intensive school‐to‐work transition program that explored occupational interests in relation‐to‐work opportunities. Results of a 1‐way analysis of covariance indicated that severity of disability had a significant effect on the employment outcomes of participants despite interest‐job matching. Although participants experienced positive employment outcomes in terms of job entry, these outcomes may not necessarily translate into higher earnings.