1. Eighteen technicians in a cell phone repair shop are randomly selected to participate in a study comparing two screen repair techniques. They are randomly assigned one of the two techniques. The manager trains 9 technicians on one technique and trains the other 9 technicians on the second technique. He then records the number of screen repairs each technician does in one week. Which inferential statistical test would be most appropriate for this scenario?

a.A one-sample z-test

b.A paired t-test

c.A chi-square goodness-of-fit test

d.A one-sample t-test

e.A two-sample t-test

2. Oscar, an MMA instructor at Fight for Fit, selected random samples of 260 students from a nearby community college and 260 students from a nearby 4-year university to compare levels of physical fitness. The mean and standard deviation of the fitness levels of the community college students were 91 and 17 respectively. The mean and standard deviation of the fitness levels of the 4-year university students were 96 and 19 respectively. He conducted a two-sided t-test with a resulting t-value of 3.16. If = 0.10, what is an appropriate conclusion from this study?

a.Because the sample means only differ by five, the population means are not significantly different.

b.Because the second group has a larger standard deviation, their mean fitness score is significantly higher.

c.Because the second group has a larger standard deviation, the mean fitness score of the first group is significantly higher.

d.Because the p-value is less than = 0.10, the mean fitness scores for the two groups of students are significantly different.

e.Because the p-value is greater than = 0.10, the mean fitness scores for the two groups of students are not significantly different.

3. Which of the following statements would be appropriate to investigate a claim that the mean speed of drivers through town exceeds the posted limit of 30 miles per hour?

a.The null hypothesis states the mean speed of drivers in this town is less than 30 miles per hour.

b.The null hypothesis states the mean speed of drivers in this town is greater than 30 miles per hour.

c.The alternative hypothesis states the mean speed of drivers in this town is greater than 30 miles per hour.

d.The alternative hypothesis states the mean speed of drivers in this town is less than 30 miles per hour.

e.The alternative hypothesis states the mean speed of drivers in this town is less than or equal to 30 miles per hour.

4. A t statistic was used to conduct a test of the null hypothesis H0: = 7 against the alternative Ha: 7, with a p-value equal to 0.034. A two-sided confidence interval for is to be considered. Of the following, which is the largest level of confidence for which the confidence interval will NOT contain 7?

a.A 90% confidence level

b.A 93% confidence level

c.A 95% confidence level

d.A 97% confidence level

d.A 99% confidence level

5. Fluoxetine, a generic anti-depressant, claims to have, on average, at least 20 milligrams of active ingredient. An independent lab tests a random sample of 80 tablets and finds the mean content of active ingredient in this sample is 18.7 milligrams with a standard deviation of 5 milligrams. If the lab doesn't believe the manufacturer's claim, what is the approximate p-value for the suitable test?

a.0.0226

b.0.4885

c.0.5115

d.0.15

e.0.0113

6. Buyers are skeptical of an ATV advertisement that claims the newest model 4-wheeler gets an average of 17 miles per gallon. They believe the dealer is understating the average. Which null and alternative hypotheses should the buyers test? Let represent the true average gas mileage.

a.H0: > 17 miles per gallon, Ha: 17 miles per gallon

b.H0: 17 miles per gallon, Ha: < 17 miles per gallon

c.H0: = 17 miles per gallon, Ha: > 17 miles per gallon

d.H0: = 17 miles per gallon, Ha: < 17 miles per gallon

e.H0: = 17 miles per gallon, Ha: 17 miles per gallon