1. A researcher wants to evaluate the learning ability of college students with various background sounds during learning. She randomly divides 21 participants into three groups. All students study a passage of text for 30 minutes. Those in group 1 study with background sound at a constant volume in the background. Those in group 2 study with background sound that changes volume randomly. Those in group 3 study with no sound at all. After studying, all students take a 10-point multiple choice test about the material. Their scores follow:

Constant sound Random sound No sound

7 5 5

4 5 6

6 3 7

8 4 9

6 4 8

6 6 7

9 2 6

a)What kind of test would you need to run?

b)What is the independent variable (or factor)?

c)What is the dependent variable?

d)What is the statistical notation (for some types of tests, this answer should include the post-hoc notations AS WELL as the overall statistical notation)?

e)Is the test significant? How do you know? (for some types of tests, this answer should include the post-hoc significance AS WELL as the overall significance)

f)What are the means that should be reported (If this is an ANOVA/factorial please include all means to be reported)?

g)What is the complete interpretation (in order to receive full credit you need to include all statistical notation as well as an interpretation of what they mean in context)

2. In order to better prepare for her 8:00am classes, a statistics graduate student designs an experiment to see how various strategies improve test scores. Getting extra sleep and drinking coffee are often said to be good ways to improve focus in class. She assigns half of her participants to 4 hours of sleep the night before a test and the other half to 8 hours. Within these groups, half of the participants are given 50mg of caffeine the morning of the test and the other half are given 100mg of caffeine. She then measures exam performance on a test with scores ranging from 1-15.

4 hours of sleep 8 hours of sleep

50mg of caffeine 10 14

7 12

9 15

7 11

10 12

8 10

9 12

100mg of caffeine 13 11

10 13

11 9

9 14

15 12

11 10

10 13

a)What kind of test would you need to run?

b)What is the independent variable (or factor)?

c)What is the dependent variable?

d)What is the statistical notation (for some types of tests, this answer should include the post-hoc notations AS WELL as the overall statistical notation)?

e)Is the test significant? How do you know? (for some types of tests, this answer should include the post-hoc significance AS WELL as the overall significance)

f)What are the means that should be reported (If this is an ANOVA/factorial please include all means to be reported)?

g)What is the complete interpretation (in order to receive full credit you need to include all statistical notation as well as an interpretation of what they mean in context)

What do these results suggest? Is there an ideal sleep/caffeine combination that appears to be the most effective or particularly ineffective?