10.30 [EX10-030] Ten subjects with borderlinehigh cholesterol levels were recruited for a study.

The study involved taking a nutrition education class. Cholesterol readings were taken before the class and 3 months after the class.

Subject 1 2 3 4 5 6 7 8 9 10 Preclass 295 279 250 235 255 290 310 260 275 240 Postclass 265 266 245 240 230 230 235 250 250 215 Let d  preclass cholesterol  postclass cholesterol.

Use the following Excel output to test the null hypothesis that the population mean difference equals zero versus the alternative hypothesis that the population mean difference is positive at

  0.05. Rejection of the null hypothesis would indicate that the (population) average cholesterol level after the class is lower than the average level before the class. Assume normality.

t-Test: Paired Two Sample for Means Pretest Posttest Mean 268.9 242.6 Variance 618.7666667 256.4888889 Observations 10 10 Hypothesized mean 0 difference df 9 t Stat 3.394655392 P(T t) one-tail 0.003970146 t Critical one-tail 1.833113856