1. In a study of the effect of anxiety on the need for affiliation, participants were told either that they would either be giving a speech to a large audience of peers (high anxiety) or that they would be speaking to one experimenter (low anxiety). Subjects were then given a choice between waiting alone before speaking or waiting in the company of others. Below are the number of participants who chose to wait alone or with others in the high and low anxiety conditions. Test the null hypothesis that anxiety had no effect on whether people chose to wait alone or with others. (34 points)
High anxiety Low anxiety
Alone 14 21
With others 20 10
a. Research Problem
b. Statistical Hypotheses
c. Decision Rule
d. Calculations
e. Decision
f. Interpretation
2. A purple skittles lover is interested in knowing whether skittle colors are equally distributed in each bag. They open up a bag of skittles and count each color. Their data are below. Test the null hypothesis that the probability of getting any color is equal. (34 points)
Red Orange Yellow Green Purple
8 7 12 14 9
a. Research Problem
b. Statistical Hypotheses
c. Decision Rule
d. Calculations
e. Decision
f. Interpretation
For each of the following questions, please specify what statistical test should be used. The correct answer can be any test that we covered this semester from correlation through chi square. (4 points each)
3. In a test of the decay theory of memory, participants memorized a list of nonsense syllables and were tested for recall after one hour and then four hours. What statistical test should be used to test the null hypothesis that delay had no effect on their recall scores?
4. Researchers are interested in whether the way instructions are delivered to jurors affects their decision making. They have two groups. In one group the jurors are verbally given instructions from the judge. In the second group the jury is given written instructions to read. What test would the researchers use to test the null hypothesis that how the instructions are given does not affect the jury’s decision making process?
5. A teacher thinks that she has an especially gifted class. She wants to compare their standardized test scores to those for the entire population of 4th graders. She knows that district wide the average exam score was a 430 with a standard deviation of 12. Her class of 18 students scored a 495. What test would you use to test the null hypothesis that her class did not do score higher than the rest of the district?
6. An experimenter is interested in testing whether listening to music improves learning how to solve complex equations. She has a control group complete a learning task without music and then an experimental group that listens to current popular music while completing the same task. What test would you use to test the null hypothesis that music does not have an effect on learning?
7. A professor believes there is a relationship between attendance and test scores. What test would she use to test the null hypothesis that there is no link between attendance and performance on a test?
8. Administration at a university believes that students who live on campus during the semester have higher levels of satisfaction with their experience at the university than students living in different off campus options. They sample 20 students who live on campus, 20 who live with roommates in off campus housing, and 20 who live at home with their families while attending classes, and then measure their satisfaction with their experience as students at the university. What test would the researchers use to test their hypothesis about student satisfaction?
9. The director of a juvenile drug rehabilitation center wants to see how their relapse rates compare to the state average. She knows the state average, but does not know the standard deviation for the state’s relapse rate. What test would she use to test the null hypothesis that her facility does not differ from the state average?
10. The matching hypothesis states that partners in romantic relationships tend to be well matched for attractiveness. Researchers are interested in seeing if this hypothesis generalizes to same sex couples. The researchers collect pictures of the faces of both partners in 30 same sex relationships, and have a group of trained coders rate how attractive each partner is. What test would the researchers use to test the null hypothesis that there is no difference in the attractiveness of same sex partners?
