Multiple-response (or pick any/c) categorical variables summarize responses to survey questions that ask "pick any" from a set of item responses. Extensions to loglinear model methodology are ...proposed to model associations between these variables across all their items simultaneously. Because individual item responses to a multiple-response categorical variable are likely to be correlated, the usual chi-square distributional approximations for model-comparison statistics are not appropriate. Adjusted statistics and a new bootstrap procedure are developed to facilitate distributional approximations. Odds ratio and standardized Pearson residual measures are also developed to estimate specific associations and examine deviations from a specified model.
Survey respondents are often prompted to pick any number of responses from a set of possible responses. Categorical variables that summarize this kind of data are called pick any/c variables. Counts ...from surveys that contain a pick any/c variable along with a group variable (r levels) and stratification variable (q levels) can be marginally summarized into an r x c x q contingency table. A question that may naturally arise from this setup is to determine if the group and pick any/c variable are marginally independent given the stratification variable. A test for conditional multiple marginal independence (CMMI) can be used to answer this question. Since subjects may pick any number out of c possible responses, the Cochran (1954, Biometrics 10, 417-451) and Mantel and Haenszel (1959, Journal of the National Cancer Institute 22, 719-748) tests cannot be used directly because they assume that units in the contingency table are independent of each other. Therefore, new testing methods are developed. Cochran's test statistic is extended to r x 2 x q tables, and a modified version of this statistic is proposed to test CMMI. Its sampling distribution can be approximated through bootstrapping. Other CMMI testing methods discussed are bootstrap p-value combination methods and Bonferroni adjustments. Simulation findings suggest that the proposed bootstrap procedures and the Bonferroni adjustments consistently hold the correct size and provide power against various alternatives.
Group testing has long been recognized as a safe and sensible alternative to one-at-a-time testing in applications wherein the prevalence rate p is small. In this article, we develop an empirical ...Bayes (EB) procedure to estimate p using a beta-type prior distribution and a squared-error loss function. We show that the EB estimator is preferred over the usual maximum likelihood estimator (MLE) for small group sizes and small p. In addition, we also discuss interval estimation and consider the use of other loss functions perhaps more appropriate in public health studies. The proposed methods are illustrated using group-testing data from a prospective hepatitis C virus study conducted in Xuzhou City, China.
Many survey questions allow respondents to pick any number out of c possible categorical responses or "items". These kinds of survey questions often use the terminology "choose all that apply" or ..."pick any". Often of interest is determining if the marginal response distributions of each item differ among r different groups of respondents. Agresti and Liu (1998, 1999) call this a test for multiple marginal independence (MMI). If respondents are allowed to pick only 1 out of c responses, the hypothesis test may be performed using the Pearson chi-square test of independence. However, since respondents may pick more or less than 1 response, the test's assumptions that responses are made independently of each other is violated. Recently, a few MMI testing methods have been proposed. Loughin and Scherer (1998) propose using a bootstrap method based on a modified version of the Pearson chi-square test statistic. Agresti and Liu (1998, 1999) propose using marginal logit models, quasisymmetric loglinear models, and a few methods based on Pearson chi-square test statistics. Decady and Thomas (1999) propose using a Rao-Scott adjusted chi-squared test statistic. There has not been a full investigation of these MMI testing methods. The purpose here is to evaluate the proposed methods and propose a few new methods. Recommendations are given to guide the practitioner in choosing which MMI testing methods to use.
Selective attention, particularly during the processing of emotionally evocative events, is a crucial component of adolescent development. We used functional magnetic resonance imagining (fMRI) with ...adolescents and adults to examine developmental differences in activation in a paradigm that involved selective attention during the viewing of emotionally engaging face stimuli. We evaluated developmental differences in neural activation for three comparisons: (1) directing attention to subjective responses to fearful facial expressions relative to directing attention to a nonemotional aspect (nose width) of fearful faces, (2) viewing fearful relative to neutral faces while attending to a nonemotional aspect of the face, and (3) viewing fearful relative to neutral faces while attention was unconstrained (passive viewing). The comparison of activation across attention tasks revealed greater activation in the orbital frontal cortex in adults than in adolescents. Conversely, when subjects attended to a nonemotional feature, fearful relative to neutral faces influenced activation in the anterior cingulate more in adolescents than in adults. When attention was unconstrained, adolescents relative to adults showed greater activation in the anterior cingulate, bilateral orbitofrontal cortex, and right amygdala in response to the fearful relative to neutral faces. These findings suggest that adults show greater modulation of activity in relevant brain structures based on attentional demands, whereas adolescents exhibit greater modulation based on emotional content.
Bilder discusses the new flagstick dilemma for putting in golf. To simplify and speed up play, the governing bodies for the rules of golf - the US Golf Association (USGA) and the R&A- changed the ...rule regarding ball contact (Rule 13.2a). The USGA stated that it is expected that there is no advantage in being able to putt with the unattended flagstick in the hole. The majority of touring professional golfers have decided to take the flagstick out since the rule change, citing reasons such as tradition and fear the flagstick might reduce their probability of making a putt.
Females appear to be more sensitive and responsive to social cues, including threat signals, than are males. Recent theoretical models suggest that developmental changes in brain functioning play ...important roles in the emergence of such gender differences.
We used functional magnetic resonance imaging to examine developmental and gender differences in activation of neural structures thought to mediate attention to emotional faces depicting varying degrees of threat. Analyses focused on the orbitofrontal cortex, amygdala, and anterior cingulate cortex during the evaluation of threat conveyed by faces. Healthy adolescents (
n = 17; 53% male) and adults (
n = 17; 53% male) were scanned while they rated how threatening pictures of neutral and emotional (angry, fearful, or happy) faces appeared.
Results indicate significant interactions among age, gender, and face type for activation during explicit threat monitoring. In particular, adult women activated orbitofrontal cortex and amygdala selectively to unambiguous threat (angry) cues, while adult men showed a less discriminating pattern of activation. No gender differences were evident for adolescents, who as a group resembled adult males.
These findings suggest that there are gender differences in patterns of neural responses to emotional faces that are not fully apparent until adulthood.
Software and data citation are emerging best practices in scholarly communication. This article provides structured guidance to the academic publishing community on how to implement software and data ...citation in publishing workflows. These best practices support the verifiability and reproducibility of academic and scientific results, sharing and reuse of valuable data and software tools, and attribution to the creators of the software and data. While data citation is increasingly well-established, software citation is rapidly maturing. Software is now recognized as a key research result and resource, requiring the same level of transparency, accessibility, and disclosure as data. Software and data that support academic or scientific results should be preserved and shared in scientific repositories that support these digital object types for discovery, transparency, and use by other researchers. These goals can be supported by citing these products in the Reference Section of articles and effectively associating them to the software and data preserved in scientific repositories. Publishers need to markup these references in a specific way to enable downstream processes.
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