A researcher wants to test the effect of amount of sleep on memory. There are four groups: 2 hours of sleep, 4 hours of sleep, 6 hours of sleep, and 8 hours of sleep. Each group contains 5 people, for a total sample size of 20. Participants in the four groups are allowed to sleep only the number of hours assigned to the group the night before the test. On the day of the test, they are given a series of numbers and are tested on their ability to remember the numbers. The scores on the memory test are shown below: Group 1, 2 hours sleep: 2, 3, 4, 5, 6 (Mean: 4) Group 2, 4 hours sleep: 2, 3, 4, 7, 8 (Mean: 4.8) Group 3, 6 hours sleep: 9, 10, 10, 11, 13 (Mean: 10.6) Group 4, 8 hours sleep: 9, 10, 10, 10, 13 (Mean: 10.4)

This semester, we have talked about creating random samples as well as desirable qualities of random samples. Other than randomness, one quality of random samples that we have talked about is representation. Using your knowledge of that concept, consider this problem. At a college, 29% of the students are in their first year, 27% are in their second year, 25% in their third, and 19% in their fourth. You take a survey of students and when you classify them by year of study, you have 49, 70, 56, and 25 students in their first, second, third, and fourth years respectively. The table below highlights this information. Year of School First Second Third Fourth Total College Percents Sample Counts Expected Counts 27% 70 25% 56 29% 19% 49 25 200 58 54 50 38 Under the assumption that we think the college enrollment percentages should match our sample, and that therefore our sample represents the college: a) What would the critical value be? (use a = 0.05) b) Find the test statistic to test (c)…

A biologist is studying the composition of birds on a lake and counts 61 ducks, 17 geese, 11 cranes, 15 swans, and 6 herons. From previous studies performed around the same time of the year, she expects 50% of the birds to be ducks, 23% to be geese, 12% to be cranes, 10% to be swans, and 5% to be herons. What are the expected and observed counts? Select one. Expected = 55 ducks, 25 geese, 13 cranes, 11 swans, and 6 herons Observed = 61 ducks, 17 geese, 11 cranes, 15 swans, and 6 herons Expected = 61 ducks, 17 geese, 11 cranes, 15 swans, and 6 herons Observed 55 ducks, 25 geese, 13 cranes, 11 swans, and 6 herons %3D Expected = 55 ducks, 25 geese, 13 cranes, 11 swans, and 6 herons Observed = 55 ducks, 25 geese, 13 cranes, 11 swans, and 6 herons %3D %3D Expected = 61 ducks, 17 geese, 11 cranes, 15 swans, and 6 herons Observed = 61 ducks, 17 geese, 11 cranes, 15 swans, and 6 herons

Do people feel hungrier after sampling a healthy snack?  Researchers randomly assign volunteers into one of three groups.  The people in the first group were asked to taste a snack that was billed as a new health bar containing high levels of protein, vitamins, and fiber.  The people in the second group were asked to taste the same snack but there told it was a tasty chocolate bar with a raspberry center.  After tasting the snack, participants were asked to rate their hunger on a scale from 1 (not at all hungy) to 7 (very hungry).  The people in the third group were asked to rate their hunger but were not given a snack.   Healthy Tasty No Snack 8 3 3 7 1 3 7 3 5 4 2 6 5 6 5 ­a.  Perform a complete one-way ANOVA hypothesis test.  Test at the .05 level of significance.