Many Americans complain about being sleep deprived. A team of psychologists researched the reasons for this sleep deprivation. After determining that one reason was poor time management, they devised a program to help people manage their time better. They recruited a random sample of 30 people at a major shopping center and randomly split them into three groups of size 10. Group 1 (the controls) received a logbook asking them to record the number of hours slept for a week but nothing else. Group 2 (the informed group) was shown a video to help improve time management. Group 3 (the intervention) participated in a two-day training course on improving time management. Groups 2 and 3 were also asked to keep records for one week on the number of hours slept. The psychologists were interested in learning if providing information or an intervention affects sleep time. After consulting a statistics manual, they decided to use ANOVA for analyzing the data. Which of the following assumptions is required for the validity of this statistical procedure?
A)equality of standard deviations for the three comparison populations
B)equality of means for the three comparison populations
C)matching of the study participants in the three groups to make sure they have similar habits prior to intervention
D)nothing; the psychologists randomized and the total sample size is 30

Question

Quizplus · Accepted Answer

One of the assumptions required for ANOVA is the equality of variances or standard deviations among the comparison populations. This assumption ensures that the groups being compared have similar levels of variability in their data. In this case, it is important to test for this assumption to make sure that the sample groups are comparable and the statistical test is valid.

Many Americans Complain About Being Sleep Deprived