Jessi conducts a study to determine whether early voting in an election affects how informed the person is when they vote. She theorizes that people who vote early are more motivated to vote and will therefore spend more time becoming informed about the candidates. She divides her sample into early voters (n = 319) and non-early voters (n = 1,240). She asks each person how much time they spent learning about the candidates and finds that early voters spent an average of 2.4 hours (S_D = 0.53) educating themselves, while the non-early voters spent an average of 2.2 hours (S_D = 0.62) educating themselves.

a. Explain why an unpaired-samples t-test is appropriate for these data.

b. What is the null hypothesis for these data?

c. What is the α for this example?

d. Given Jessi’s theory, is a one- or a two-tailed hypothesis appropriate for this NHST?

e. Given your response to item (d), what is the appropriate alternative hypothesis for this example?

f. Calculate the degrees of freedom for the data.

g. Find the tcrit value.

h. Calculate the pooled standard deviation and the pooled variance for these data.

i. Calculate the tobs value for the data.

j. Should you reject or retain the null hypothesis?

k. Find a p-value for this example.

l. Should Jessi worry about Type I or Type II error?

m. Calculate and interpret Cohen’s d for this example.

n. Do the data in this example violate any assumptions? If so, which one(s)?