Read the following paragraph and answer the five questions, which follow :

The experimental psychologist wanted to explore whether the noise adversely affects the reaction time (RT). She also wanted to explore whether the stress level would moderate the effect of noise. She varied noise at three levels - low (30 decibels), moderate (60 decibels) and high (90 decibels). She varied stress at two levels - low and high. From the initial pool of college students, subjects were randomly assigned to different groups. However, a few subjects could not turn up to the laboratory due to vacation. In all, two hundred and ninety seven subjects participated in the experiments. Each subject, in each group, was tested for simple RT. disjunctive RT. and choice RT. The theory and preliminary analyses indicated the three types of RT were moderately correlated. The covariance matrices, showing the co variances among the three types of RTs. were found to be quite similar for all the groups. The multivariate analysis of variance (MANOVA) results were computed to explore the group differences in means. As the most common practice is, four test criteria (Pillais criterion. Wilks' criterion. Hotelling's criterion, and Roy's criterion) were obtained. Among the different results obtained in this work. one interesting finding was that the stress moderated the effect of noise level on reaction time.