In 1970, the mean time between eruptions of the Old Faithful geyser was 66 minutes. Refer to

Question:

In 1970, the mean time between eruptions of the Old Faithful geyser was 66 minutes. Refer to the intervals (in minutes) between eruptions for the more recent data listed in Data Set 16 of Appendix B.
a. Test the claim of Yellowstone National Park geologist Rick Hutchinson that eruptions now occur at intervals that are longer than in 1970.
b. Construct a 95% confidence interval for the mean time between eruptions.