Question

A survey of Internet users reported that 20% 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 28% from a survey taken two years before. Assume that the sample sizes are both 1381. Using a significance test, evaluate whether or not there has been a change in the percent of Internet users who download music. Provide all details for the test. (Round your value for z to two decimal places. Round your P-value to four decimal places.)

z	=
P-value	=

Summarize your conclusion.

____We conclude that the means are not different.We conclude that the proportions are different.  

____ We cannot draw any conclusions using a significance test for this data.

____We conclude that the means are different.

____We conclude that the proportions are not different.

Also report a 95% confidence interval for the difference in proportions. (Round your answers to four decimal places.)

( ____ , _____ ) Answers

  ,
Explain what information is provided in the interval that is not in the significance test results.

____The interval does not provide any more information than the significance test would tell us.

____The interval tells us there was a significant change in music downloads, but the test statistic is inconclusive.    

____The interval shows no significant change in music downloads.

____The significance test does not indicate the direction of change, but the interval shows that the music downloads decreased.

____The interval gives us an idea of how large the difference is between the first survey and the second survey.

THANKS

Answer 1