Computing aspects of power for multiple regression

Rules of thumb for power in multiple regression research abound. Most such rules dictate the necessary sample size, but they are based only upon the number of predictor variables, usually ignoring other critical factors necessary to compute power accurately. Other guides to power in multiple regression typically use approximate rather than precise equations for the underlying distribution; entail complex preparatory computations; require interpolation with tabular presentation formats; run only under software such as Mathmatica or SAS that may not be immediately available to the user; or are sold to the user as parts of power computation packages. In contrast, the program we offer herein is immediately downloadable at no charge, runs under Windows, is interactive, self-explanatory, flexible to fit the user’s own regression problems, and is as accurate as single precision computation ordinarily permits.     

Beyond binary judgments: Prime validity modulates masked repetition priming in the naming task

Bodner and Masson (2001) reported that masked repetition priming of lexical decisions is often greater when the repetition primes appear on a high, rather than a low, proportion of trials. They suggested that processing episodes are constructed for masked primes and that recruitment of those episodes is affected by the probability that the prime will be useful for processing the target. If context-sensitive recruitment of primes is a general mechanism, a similar effect should also occur in a nonbinary response task. In accord with this hypothesis, using the naming task and a 45-msec prime duration, we show that masked repetition priming effects for uppercase words, case-alternated words, and pseudohomophones were greater when .8 rather than .2 of the trials involved repetition (vs. unrelated) primes. Prime validity effects are consistent with a memory recruitment view of priming but may be difficult to explain using activation-based mechanisms.     

The temporal course of the frustration effect

General activity subsequent to reward (R) and nonreward (N) was monitored at 5-sec intervals with a stabilimeter in the runway goal box. Activity of never-rewarded control Ss was also measured. In Expt 1 it was found that the frustration effect (difference between N- and R-trial activities) disappeared after about 40 sec of goal box confinement. This disappearance of the frustration effect was due to activity increase on R trials rather than activity decrease on N trials as a function of time. Comparison of N-trial activity with control group activity indicated that frustration does not dissipate within 60 sec. Expt 2 investigated activity following reward and nonreward as a function of reward magnitude. Evidence from these experiments suggests that the late R-trial activity increase results from frustration, possibly conditioned to apparatus cues on N trials.     

INCREASING SPONTANEOUS PLAY BY SUPPRESSING SELF-STIMULATION IN AUTISTIC CHILDREN1

Appropriate play with toys was studied in two autistic children with high occurrences of self-stimulatory behavior. Each child participated in the experimental sessions in an A-B-A design, where “A” refers to baseline sessions and “B” refers to self-stimulation suppression sessions. It was found that: (a) during the baseline sessions, the children exhibited low levels of play and high levels of self-stimulatory behavior; (b) the per cent of unreinforced, spontaneous, appropriate play increased when self-stimulatory behavior was suppressed; and (c) when the suppression of self-stimulation was discontinued, the per cent of self-stimulation and that of appropriate play approached their presuppression levels. These results seem particularly significant because they identify a set of conditions under which spontaneous appropriate behavior, uncommon in autistic children, occurs at an increased level.     

The effects of multi-component,assessment-based curricular modifications on the classroom behavior of children with emotional and behavioral disorders

In this study, academic task assignments were modified in an effort to improve the conduct and task performance of three students with emotional and behavioral disorders. Functional assessments, including interviews and direct observations, were conducted to identify variables that affected the performance of each student during problematic assignments. The assessments implicated several variables for each student. These variables were then used as guides to modify the problematic tasks. The modifications resulted in reduced levels of problem behaviors and increased rates of task engagement, work productivity and accuracy for each of the students. The effects were demonstrated within ongoing academic activities and replicated through the use of reversal designs. The findings are discussed in relation to the practical process of functional assessment and the relevance of curricular and instructional arrangements to the occurrence of disruptive behavior.     

Temporal delay,type of forewarning,and resistance to influence

Previous researchers have manipulated forewarning by providing premessage information about the topic and position of the upcoming communication, or the communicator's persuasive intent. Subjects in the present experiment were force-warned either 10 min prior to the communication, or just before the message began of the speaker's topic and position, persuasive intent, or topic only. As hypothesized, forewarning of the communicator's persuasive intent inhibited persuasion regardless of the length of the delay period, but forewarning of the topic and position required a delay in order to confer resistance to subsequent persuasion, suggesting that although both manipulations have been called “forewarning they may lead to reduced persuasion through different mechanisms. Foreknowledge of the source's topic, but not his position also increased resistance to persuasion when followed by a delay period. The results were discussed in terms of both cognitive and motivational mechanisms that may underly the persuasion inhibiting effects of forewarning.     

Behavioral Indicators of Interpersonal Attraction1

The laboratory study of attraction is based almost exclusively on verbal measures of the dependent variable. Various findings suggest that the physical distance separating two individuals indicates the degree of attraction between them. In two experiments, attitude similarity between a subject and two stooges was manipulated. Females were more attracted to and sat more closely beside a similar than a dissimilar stranger (p < .01); males were more attracted to and sat directly across from a similar rather than a dissimilar stranger (p < .02).     

Family Processes and Treatment Outcome in the MTA: Negative/Ineffective Parenting Practices in Relation to Multimodal Treatment

To elucidate processes underlying therapeutic change in a large-scale randomized clinical trial, we examined whether alterations in self-reported parenting practices were associated with the effects of behavioral, medication, or combination treatments on teacher-reported outcomes (disruptive behavior, social skills, internalizing symptoms) in children with attention-deficit hyperactivity disorder (ADHD). Participants were 579 children with Combined-type ADHD, aged 7–9.9 years, in the Multimodal Treatment Study of Children with ADHD (MTA). We uncovered 2 second-order factors of parenting practices, entitled Positive Involvement and Negative/Ineffective Discipline. Although Positive Involvement was not associated with amelioration of the school-based outcome measures, reductions in Negative/Ineffective Discipline mediated improvement in children's social skills at school. For families showing the greatest reductions in Negative/Ineffective Discipline, effects of combined medication plus behavioral treatment were pronounced in relation to regular community care. Furthermore, only in combination treatment (and not in behavioral treatment alone) was decreased Negative/Ineffective Discipline associated with reduction in children's disruptive behavior at school. Here, children in families receiving combination treatment who showed the greatest reductions in Negative/Ineffective Discipline had teacher-reported disruptive behavior that was essentially normalized. Overall, the success of combination treatment for important school-related outcomes appears related to reductions in negative and ineffective parenting practices at home; we discuss problems in interpreting the temporal sequencing of such process-outcome linkages and the means by which multimodal treatment may be mediated by psychosocial processes related to parenting.     

A benevolent conceptualization of marital power: The case of depression

Treatment of the depressed client with low self-esteem, external locus of control, and an absent spouse often is frustrating due to the limitations of modifying the social context. An approach to the problem using a systemic view which is based on examining the notion of power and examining the problems in their context is presented. Interventions which sidestep the temptation of emphasizing self-esteem of the client and, instead, utilize client strengths and interactional dynamics within the marriage are presented.