. An experimenter was interested in studying the effects of sleep deprivation on the ability to detect moving objects on a radar screen. A total of 20 students were available for the study. The first five randomly selected subjects were assigned to Treatment Group 1 (4 hours without sleep), the next five randomly selected subjects were assigned to Treatment Group 2 (12 hours without sleep), the next five randomly selected subjects were assigned to Treatment Group 3 (20 hours without sleep), and the remaining five subjects were assigned to Treatment Group 4 (28 hours without sleep). After being deprived of sleep, each subject was given a test and the number of times they failed to spot a moving object during the set test period was recorded. The results are given in the following table:

4 Hours	12 Hours	20 Hours	28 Hours
36	38	46	76
21	45	74	66
20	46	67	62
26	22	61	44
21	40	59	61

(a) Is this study an experiment of an observational study?

(b) Give a name for the explanatory variable in this study.

(c) Give a name for the response variable in this study.

(d) The study stated that the 20 subjects were randomly assigned to one of four treatment groups. Using your calculator (with a seed value of 14), perform the randomization. Report the labels of the subjects assigned to each of the four groups.

(e) State the appropriate null and alternative hypotheses for assessing whether the mean number of failures is the same for the four sleep-deprivation conditions.

(f) Create 95% confidence intervals for the population means for each level of the experiment (e.g. 4 hours, 12 hours, etc.) and draw a spatially representative graph as I demonstrate in the ANOVA video lecture linked above.

(g) Explain what the statistical analysis reveals about the effects of sleep deprivation on the subjects' ability to detect objects while sleep deprived.