Contradicting some previous research, a new study finds that frequent use of painkillers does not substantially increase a healthy man's risk of developing hypertension. What would have been the null value in this scenario for the difference in proportions of men who developed hypertension (frequently use painkiller not frequently use painkiller)?
Q. 2Managerial training programs often teach supervisory skills. Are these training programs effective? A company psychologist administers a test to each of 10 supervisors before and after attending such a training program. Higher scores indicate increased supervisory skills. The results are used to estimate the mean improvement in supervisory skills. Give a 95 confidence interval for the population mean improvement in supervisory skills for all supervisors who take the training program.
Q. 3According to a recent survey, teenagers who eat with their families at least five times a week are more likely to get better grades in school and much less likely to have substance abuse problems. Two groups of teenagers were studied: those who eat with their families at least five times a week and those who don't. The difference in school grades and the difference in likelihood to have substance abuse problems were both found to be statistically significant. When comparing the likelihood to have substance abuse problems between the two groups, what does statistical significance mean?
Q. 4Managerial training programs often teach supervisory skills. Are these training programs effective? A company psychologist administers a test to each of 10 supervisors before and after attending such a training program. Higher scores indicate increased supervisory skills. The results are used to estimate the mean improvement in supervisory skills. Suppose the mean improvement in supervisory skills was 3 point and the standard deviation of the sampled differences was 2 points. Give the standard error of the sample mean difference.
Q. 5According to a recent survey, teenagers who eat with their families at least five times a week are more likely to get better grades in school and much less likely to have substance abuse problems. Two groups of teenagers were studied: those who eat with their families at least five times a week and those who don't. The difference in school grades and the difference in likelihood to have substance abuse problems were both found to be statistically significant. What would have been the null value in this scenario for the difference in school grades between the two groups?
Q. 6Managerial training programs often teach supervisory skills. Are these training programs effective? A company psychologist administers a test to each of 10 supervisors before and after attending such a training program. Higher scores indicate increased supervisory skills. The results are used to estimate the mean improvement in supervisory skills. Explain why this is a paired data design.
Quick Reply
