Statistics 5/10/20

Name: ______________________________

Homework Assignment #2 (out of 58 points)

1. Jessica wants to know if gender and/or college major have a significant effect on a person’s social

aptitude. To that end, she designs a social aptitude task and administers it to a group of Psychology

majors who are female, another group of Psychology majors who are male, a group of Biology majors

who are female and another group of Biology majors who are male. The data follows. What can Jessica

conclude? (40 points)

Psychology Majors – Female:

8

6

7

9

Psychology Majors – Male:

5

7

8

6

Biology Majors – Female:

7

4

8

9

Biology Majors – Male:

9

4

7

8

2. In question 1, what is/are the factor(s) and how many levels are there (of each)? (3 points)

3. In question 1, if you had conducted a t-test on social aptitude scores between males and females

(combining both majors in each case), what would your decision have been? (1 point)

4. If the distribution of social aptitude scores is approximately normal in the general population, what

proportion of samples of size n = 64 would have a mean score between 5 and 7, if µ = 6.2 and σ = 4? (5

points)

5. For each of the following scenarios, simply state WHICH technique that you have learned this

semester would be the most appropriate method to analyze the results. No calculations are necessary.

BE AS SPECIFIC AS POSSIBLE (e.g., type of hypothesis test? directional or non-directional?) (9 points)

A. Sam wants to know if students spend more time studying for midterms or for finals. She asks 30

people how many hours they studied for each exam, and records their responses. She expects that

students spend more time studying for finals.

B. Michael thinks that people who travel more report higher quality of life. To test this, Michael studies

a group of 20 people across many years. He gets them to rate their quality of life (on a scale from 1-10)

before they’ve travelled at all, again after they’ve taken their first trip abroad and again after their third

trip abroad. Michael compares the data at the three time points to see if his hypothesis is correct.

C. Meredith wants to know if a new medication affects sleep. So, she takes a sample of 81 people and

has them all take the medication for a week. During that time, those 81 people record the number of

hours they slept. If you are given M = 42, µ = 45 and σ = 8, how can you determine whether the

medication affects the number of hours people sleep.

D. In the previous question, if you were given the standard deviation for the group of 81 people only,

instead of σ, what would you do to answer the same question?