HOMEWORK 3 (Due October 29)
Question 1 (25 points
Let’s say we are researching voter turnout in three different countries. Professor Ozer has gathered data from several elections in each country and has created two hypotheses.
Hypothesis 1: Ozeristan will have a higher voter turnout than the Democratic Republic of Fisher.
Hypothesis 2: The United States of Coconut will have higher voter turnout than both Ozeristan and the Democratic Republic of Fisher.
Mean Voter Turnout (in %) Standard Deviation Sample Size (# of elections observed).
Ozeristan50 10 5
Democratic Republic of Fisher 60 10 5
United States of Coconut 70 2 5
a. Which of these countries has the most stable voter turnout rate? Why?
b. Calculate the 95% confidence interval for each country. Please report them in the following format: [lower bound, upper bound]
c. Does the evidence support Hypothesis 1? Why or why not?
d. Does the evidence support Hypothesis 2? Why or why not?
e. What would happen if we increased the sample size to 10 elections? 100 elections? No need to do the math, just tell me what would happen conceptually.
Question 2 (25 points)
a. What does it mean for something to be “statistically significant”?
b. What does it mean for something to be “substantively significant”?
c. If something is statistically significant, does that mean its also substantively significant? Why or why not?
d. Why are null findings still important and relevant?
Question 3 (25 points)
Let’s say Professor Ozer is running an experiment. In the treatment group, respondents were given a plate of cookies. In the control group, the respondents were given nothing. They were then asked how much they like Professor Ozer on a 100 point scale, with higher scores indicating that they liked him more. The results are as follows.
Mean score Standard deviation # of respondents
Treatment Group 75 15 100
Control Group 50 15 100
a. Calculate a difference of means test.
b. Is there a statistically significant difference between the two groups (p < .05)? Why?
Bonus question! (.5 points)
Who/what are you going as for Halloween?