CH12-13 exercises solutions

# CH12-13 exercises solutions - X X X X X X X X X X X X X X X...

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1 X X X X X X X X X X X X X X X X X AP Statistics Packet 12/13 X Inference for Proportions Inference for a Population Proportion Comparing Two Proportions Inference for Tables: Chi-Square Procedures Test for Goodness of Fit Inference for Two-Way Tables X X X X X

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3 12.7 TEENS AND THEIR TV SETS The New York Times and CBS News conducted a nationwide poll of 1048 randomly selected 13- to 17-year-olds. Of these teenagers, 692 had a television in their room and 189 named Fox as their favorite television network. We will act as if the sample were an SRS. (a) Use your calculator to give 95% confidence intervals for the proportion of all people in this age group who have a TV in their room and the proportion who would choose Fox as their favorite network. Check that we can use our methods. (Check assumptions.) Check assumptions for TV in room: SRS 1048 < 10% of all 13- to 17-year olds ˆ np = 692 > 10, ˆ ( 1 ) np - = 356 >10 Check assumptions for prefer FOX: SRS 1048 < 10% of all 13- to 17-year olds ˆ np = 189 > 10, ˆ ( 1 - = 859 >10 95 % 0.66 (0.631 , 0.689) C I for TV in room (0.6629(0.3429 = ± 1.96 1048 = 95 % 0.18 (0.157, 0.203) C I for preferring FOX (0.1829(0.8229 = ± 1.96 1048 = (b) The news article says, “In theory, in 19 cases out of 20, the poll results will differ by no more than three percentage points in either direction from what would have been obtained by seeking out all American teenagers.” Explain how your results agree with this statement.

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CH12-13 exercises solutions - X X X X X X X X X X X X X X X...

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