Do gender and seating arrangement in college classrooms affect student attitude? In a study at a large public university in the United States, researchers surveyed students to measure their level of feeling at ease in the classroom. Participants were shown different classroom layouts and asked questions regarding their attitude toward each layout. The following data represent feeling-at-ease scores for a random sample of 32 students (four students for each possible treatment).

(a) What is the population of interest?
(b) Is this study an experiment or an observational study? Which type?
(c) What are the response and explanatory variables? Identify each as qualitative or quantitative.
(d) Compute the mean and standard deviation for the scores in the male/U-shaped cell.
(e) Assuming that feeling-at-ease scores for males on the U-shaped layout are normally distributed with µ = 19.1 and σ = 0.8, what is the probability that you would observe a sample mean as large or larger than actually observed? Would this be unusual?
(f) Determine whether the mean feeling-at-ease score is different for males than females using a two-sample t-test for independent samples. Use the a = 0.05 level of significance.
(g) Determine whether the mean feeling-at-ease scores for the classroom layouts are different using one-way ANOVA. Use the a = 0.05 level of significance.
(h) Determine if there is an interaction effect between the two factors. If not, determine if either main effect is significant.
(i) Draw an interaction plot of the data. Does the plot support your conclusions in part (h)?
(j) In the original study, the researchers sent out e-mails to a random sample of 100 professors at the university asking permission to survey students in their class. Only 32 respondents agreed to allow their students to be surveyed.
What type of nonsampling error is this? How might this affect the results of the study?