Question

A study found that highway drivers in one states traveled ot an average soeed of 58.8 miles oer hour (MPH). Assume the population standard deviation is 6.0 MPH. Complete parts a through d below:

a). what is the probability that a sample of 30 of drivers will have a sample mean less than 57 MPH?

P(x< 57)=

b). what is the probability that a sample of 50 of drivers will have a sample mean less than 57 MPH?

P(x< 57)=

c).what is the probability that a sample of 70 of drivers will have a sample mean less than 57 MPH?

P(x< 57)=

d). Explain the difference in these probabilities

As the sample size increases, the standard errors of the mean ....... and the sample means ....... sample mean less than 57 MPH.......

thank you

Answer 1

(a) Here n= 30.

(b) Here n= 50.

(c) Here n= 70.

(d)

Ans : Increases, same, decreases