1. A prison psychologist recorded the number of rule infractions for 15 prison inmates over a six-month period to be 5, 4, 2, 4, 3, 5, 2, 0, 4, 4, 5, 5, 3, 4, and 3.
a. Make a frequency table.
b. Make a histogram based on the frequency table.
c. Describe in words the shape of the histogram.
2. Identify and solve this problem by hand.
The head of public safety notices that the average driving speed at a particular intersection averages μ = 35 mph with a standard deviation of σ = 7.5 mph. After a school speed limit sign of 20 mph is placed at the intersection, the first 40 cars travel past at an average speed of 32 mph. Using the .01 significance level, was there a significant change in driving speed?
a. Use the five steps of hypothesis testing
b. Sketch the distributions involved.
c. Figure the confidence limits for the 99% confidence interval.
3. You will have to use a combination of StatCrunch and hand calculations (e.g., effect sizes) to solve the following problems.
A social psychologist gave a questionnaire about concern for farm workers to seven participants before and after they attended a film about union organization of farm workers. The results are shown below with high scores meaning high concern. Using the .05 significance level, do these results support the hypothesis that the film affected concern for the lives of farm workers?
Scores on the Concern Measure
Participant Before After
A 17 20
B 7 4
C 10 11
D 13 15
E 8 5
F 9 8
G 11 14
a. Use the five steps of hypothesis testing.
b. Figure the effect size and find the approximate power of this study.
4. You will have to use a combination of StatCrunch and hand calculations (e.g., effect sizes) to solve the following problems.
A team of cognitive psychologists studying the effects of sleep deprivation on short-term memory decay had eight participants stay in a sleep lab for two days. Four participants were randomly assigned to a condition in which they were not permitted to sleep during that period, while the other four participants were allowed to sleep when they wanted to. At the end of the two days, the participants completed a short-term memory task that yielded the results in the table that follows. Using the .05 significance level, did sleep deprivation reduce short-term memory?
Mean Number of Letters Remembered
Sleep Deprived Normal Sleep
a. Create the appropriate graph for this problem.
b. Use the five steps of hypothesis testing.
5. A sports psychologist gave a questionnaire about healthy eating habits to randomly selected professional athletes. The results are displayed below. Using the .05 significance level, is there a difference in healthy eating habits among professionals in the three sports?
Baseball Players Basketball Players Football Players
32 27 27
27 36 23
26 25 26
35 30 20
a. Make a graph for the data set. (done already)
b. Figure the effect size of this study.
c. Conduct a planned contrast for Baseball versus Football players (using Tukey’s HSD).
6. A researcher is interested in the effects of sleep deprivation and caffeine intake on mood. Participants were randomly assigned to a sleep condition (normal or deprived) and a caffeine condition (0 cups, 2 cups, or 4 cups). After the manipulations, mood was measured (such that higher numbers indicated better mood). The results were as follows:
Normal Condition Deprived Condition
0 cups 2 cups 4 cups 0 cups 2 cups 4 cups
16 18 18 0 5 6
17 20 17 6 4 8
20 20 17 3 4 6
19 19 17 2 2 7
18 18 16 4 5 8
Analyze these data using a factorial analysis of variance and including R2 for each effect.
7. An advertising firm wanting to target people with strong desires for success conducted a study to see if such people differed in the types of television shows they watched. Randomly selected participants recorded the shows they watched for a week, then their desire for success was assessed, and finally they were divided into two groups. Low Success seekers watched 8 comedies, 15 romances, 6 documentaries, 13 dramas, and 3 news shows. High Success seekers watched 3 comedies, 3 romances, 9 documentaries, 7 dramas, and 8 news shows. Using the .05 significance level, is the distribution of type of shows watched different for participants having high and low desires for success?
a. use the five steps of hypothesis testing.
b. Figure a measure of effect size and indicate whether it is small, medium, or large.