A survey of Internet users reported that 15% downloaded music onto their compute

Question

A survey of Internet users reported that 15% downloaded music onto their computers. The filing of lawsuits by the recording industry may be a reason why this percent has decreased from the estimate of 31% from a survey taken two years before. Suppose we are not exactly sure about the sizes of the samples. Perform the calculations for the significance tests and 95% confidence intervals under each of the following assumptions. (Use previous recent. Round your test statistics to two decimal places and your confidence intervals to four decimal places.)

(iii) The sample size for the survey reporting 31% is 1000 and the sample size for the survey reporting 15% is 1600.

z=

Explanation / Answer

p1=0.31 ; n1=1000

p2=0.15 ; n2=1600

here std errror =(p1(1-p1)/n1 +p2(1-p2)/n2)1/2 =0.017

hence test staT Z =(P1-P2)/STD ERROR =0.16/0.017 =9.33

AS TEST STAT z is significantly higher ; hence we reject the null hypothesis that they both are equal

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