Investigators examined 25 singleton birth records where the mother acknowledged drinking 3 or more cups of regular coffee (not decaffeinated) per day throughout her pregnancy. The sample mean duration of those pregnancies was 275.2 days; the sample standard deviation was 10.3 days. Is there evidence to suggest that the true mean duration of singleton pregnancies is different from 280 days if the mother drinks 3 or more cups of regular coffee per day throughout her pregnancy?

a. Let Mu be the true mean duration of singleton pregnancies in which the mother drinks 3 or more cups of regular coffee per day throughout her pregnancy. State the null and alternative hypotheses in terms of Mu.

b. Carry out the appropriate analysis using the p-value method at level alpha= .05.

c. Interpret the results in a complete sentence.