Question

exercise statement: the initial pressures for bicycle tires when first filled are normally distributed, with a mean of 70 pounds per square inch (psi) and a standard deviation of 1.2 psi. a random sample of 15 tires is drawn from this population. what is the probability that the mean tire pressure of the sample is less than 69 psi? use minitab how-to

Answer 1

Below

Explanation:

70 - 69 = 1

1/1.2 is .83 S.D. below the mean for a z-score = -.83

from a z-score table this corresponds to .2033 or 20.33%