Answer:
(a) Confidence Interval for Route A is (38.61, 41.39)min
Confidence Interval for Route B is (42.07, 43.93)min
(b) No
Step-by-step explanation:
(a) Route A
Mean=40min, sd=3min, df=33.1, t=2.0675, n=20
CI = (mean + or - t×sd/√n)
CI = (40 + 2.0675×3/√20) = 40+1.39 = 41.39min
CI = (40 - 2.0675×3/√20) = 40 - 1.39 = 38.61min
CI for Route A is (38.61,41.39)min
Route B
Mean=43min, sd=2min, t=2.0675, n=20
CI = (43 + 2.0675×2/√20) = 43+ 0.93 = 43.93min
CI = (43 - 2.0675×2/√20) = 43 - 0.93 = 42.07min
CI for Route B is (42.07,43.93)min
(b) He should not believe the old timer's claim. The man saves an average of 3 minutes a day by driving Route A
