Question Set 2: Mean Exam Score

A course coordinator is examining scores on an exam. In a representative sample of 35 students, the mean exam score was 87.9 points with a standard deviation of 6.8 points.

A. Use Minitab Express to determine if there is evidence that the mean exam score is different from 90 points in the population of all test takers. Use the five-step hypothesis testing procedure outlined below. Remember to include all relevant Minitab Express output and to clearly identify your test statistic and p value. Don't do any hand calculations. [25 points]

Step 1: Check assumptions and write hypotheses

Step 2: Calculate the test statistic

Step 3: Determine the p value

Step 4: Decide to reject or fail to reject the null

Step 5: State a "real world" conclusion

B. Use Minitab Express to construct a 95% confidence interval for the mean exam score in the population. Remember to include your relevant Minitab Express output and to clearly identify your final answer. Don't do any hand calculations. [15 points]

C. What minimum sample size would be necessary to construct a 95% confidence interval for the mean exam score with a margin of error of 1 point? You will need to do hand calculations. Show all of your work.[10 points]