In 1997 a survey of 900 households showed that 140 of them u

In 1997, a survey of 900 households showed that 140 of them use e-mail. Use those sample results to test the claim that more than 15% of households use e-mail. Use a 0.05 significance level. Use this information to answer the following question. Which of the following is the hypothesis test to be conducted? What is the test statistic? What is the P-value? What is the conclusion? Is the conclusion valid today? Why or why not?

Solution

a) H0:p=0.15

H1:p>0.15

b) Z=p-P0/sqrt(P0Q0/n)

P0=0.15

p=140/900=0.155

n=900

Q0=1-P0=0.85

Z=0.42

c) p=0.3372

d) There is not sufficient evidence to support the claim that more than 15% of the households use email.

e) No, the conclusion is not valid today, becasue the popultion of charecterisitc of the use of email are chanignng rapidly.