Reference no: EM132474376

Suppose that the population of the scores of all high school seniors that took the SAT-V (SAT verbal) test this year follows a normal distribution with mean µ = 480 and standard deviation σ = 90. A report claims that 10,000 students who took part in a national program for improving one's SAT-V score had significantly better scores (at the 0.05 level of significance) than the population as a whole. In order to determine if the improvement is of practical significance one should

a. find out the actual mean score of the 10,000 students.

b. use a two-sided test rather than the one-sided test implied by the report.

c. find out the actual P-value.

Does taking garlic tablets twice a day provide significant health benefits? To investigate this issue, a researcher conducted a study of 50 adult subjects who took garlic tablets twice a day for a period of six months. At the end of the study, 100 variables related to the health of the subjects were measured on each subject and the means compared to known means for these variables in the population of all adults. Four of these variables were significantly better (in the sense of statistical significance) at the 5% level for the group taking the garlic tablets as compared to the population as a whole, and one variable was significantly better at the 1% level for the group taking the garlic tablets as compared to the population as a whole. It would be correct to conclude

a. there is good statistical evidence that taking garlic tablets twice a day provides benefits for the variable that was significant at the 1% level. We should be somewhat cautious about making claims for the variables that were significant at the 5% level.

b. there is good statistical evidence that taking garlic tablets twice a day provides some health benefits.

c. Neither choice is correct.

How well does a new medication reduce blood pressure relative to baseline? One hundred patients had their blood pressure measured before and after taking the drug. The average reduction in blood pressure for these patients is  = 30 mm Hg. Assume that the reduction in blood pressure for the new medication follows a normal distribution with unknown mean µ and standard deviation σ = 10 mm Hg. A 90% confidence interval for µ is

a. 30 ± 1.96

b. 30 ± 1.645

c. 30 ± 16.45