Question

1. Walter usually meets Julia at the track. He prefers to jog 3 miles. From long experience, he knows that for his jogging times σ = 1.40. For a random sample of 80 jogging sessions, the mean time was = 20.50 minutes. Let μ be the mean jogging time for the entire distribution of Walter’s 3-mile running times over the past several years. Find a 0.99 confidence interval for μ. Give the lower bound
2. give the upper bound

Answer 1

20.5   2.576 ( 1.4 / 80 )

20.5   0.4032

( 20.097 , 20.903 )

At 99 % , CI for Mean is ( 20.097 , 20.903 )

Lower Bound = 20.097

Upper Bound = 20.903