28 When 3012 adults were surveyed in a poll 27 said that the

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When 3012 adults were surveyed in a poll, 27% said that they use the Internet. Is it okay for a newspaper reporter to write that \"1/4 of all adults use the Internet\"? Why or why not? Identify the null hypothesis, alternative hypothesis, test statistic, P-value, conclusion about the null hypothesis, and final conclusion that addresses the original claim. Use the P-value method. Use the normal distribution as an approximation of the binomial distribution.

HO: p   is > or, < or, = to or, not= to 0.25, 0r 0.75?_______

H1: p   is > or, < or, = to or, not= to 0.25 or 0.75?_______

b. What is the test statistic? z= _______

(Round the final answer to two decimal places as needed.)

c. What is the P-value?    P-value= ________

(Round to four decimal places as needed.)

d. What is the conclusion?

A. There is sufficient evidence to support the claim.

B. There is not sufficient evidence to support the claim

e. Is the conclusion valid today? Why or why not?

A.Yes, the conclusion is valid

B.No, the conclusion is not valid

C. You can make no decisions about the validity of the conclusion

Solution

HO: p   is = 0.25

H1: p not= to 0.25

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(b) The test statistic is

Z=(phat-p)/sqrt(p*(1-p)/n)

=(0.27-0.25)/sqrt(0.25*0.75/3012)

=2.53

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(c) It is a two-tailed test.

So the 2*P(Z>2.53) =0.0114 (from standard normal table)

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(d)A. There is sufficient evidence to support the claim.

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(e)A.Yes, the conclusion is valid