Mrs. Warrack, a retired archeologist, enjoys hiking in BadgerCreed every other day. Usually she travels 3 miles per hike. Duringthe past year Mrs. Warrack has recorded the times of her hikes. Fora sample of 90 times, the mean was x ?=23.18 minutes and thestandard deviation was s = 1.87 minutes. Let ? mean the mean hikingtime for the entire distribution of Mrs. Warrack’s 3-mile hiketimes (taken over the past year )   Â
How many degrees of freedom are there? Â Â Â
Find a 0.95 confidence interval ?. Use t*= 1.987 .
