Question

A recent personalized information sheet from your wireless phone carrier claims that the mean duration of all your phone calls was μ=3.2 minutes with a standard deviation of σ=1.7 minutes. From a random sample of n=40 calls, your parents computed a sample mean of x overbar=3.6 minutes and a sample standard deviation of s=2.3 minutes. Complete parts a through e below.

a. Sketch the population distribution for the duration of your phone calls. What are its mean and standard​ deviation?

b.What are the mean and standard deviation of the data​ distribution?

c.Find the mean and standard deviation of the sampling distribution of the sample mean.

d. Is the sample mean of 3.6 minutes unusually​ high? Find its​ z-score and comment.

Since z=_____ the sample mean _____ unusually high.

e. Your parents told you that they will kick you off the plan when they find a sample mean larger than 3.7

minutes. How likely is this to​ happen?

​P(x overbar greater than>3.7​minutes)=

Answer 1