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Using the MOE give in in the article, what is the 95% confidence interval for the true proportion of
Americans in favor of allowing gay and lesbian couples to marry? ✔Correct Answer-51.3% to 54.7%
1b ✔Correct Answer-No. Could say the sample suggests a majority of Americans favor...
1c ✔Correct Answer-No. That's sampling variability.
What are the Pew Center poll's sample and statistic? ✔Correct Answer-We don't know the size of
the sample, but the implication is that it is a sample of Americans. That statistic reported is that 67%
accept scientific evidence of global warming.
What are the population and the parameter? ✔Correct Answer-Population is all Americans.
Parameter would be the true proportion of all Americans who accept scientific evidence of global
warming, if it were possible to ask all Americans.
Using the MOE given in the article, construct a confidence interval for the true proportion of all
American who accept the scientific evidence of global warming. ✔Correct Answer-67% +/- 2.9%
What are the sample and the statistic for the CBS News poll? ✔Correct Answer-The sample is the
1110 adults contacted by telephone, and the statistic is the 54% who say they support stricter gun
laws.
What are the population and the parameter? ✔Correct Answer-The population is all U.S. adults,
and the parameter is the proportion of all adults who would have said they back stricter gun laws,
had it been possible to ask all of them.
Compute an 80% confidence interval for the true proportion of Americans who "generally back
stricter gun laws." What percent decrease in width is this interval from a 95% interval? ✔Correct
Answer-The width of the interval went from 0.06 to 0.04. That is a 33.3% decrease in the interval
width.
What is the 95% confidence interval for the true thriving rates among graduates of public selective
institutions? ✔Correct Answer-(0.10, 0.12)
What is the 95% confidence interval for the true thriving rates among graduates of private not-for-
profit selective institutions? ✔Correct Answer-(0.11, 0.13)
What is the 95% confidence interval for the true thriving rates among graduates of public non-
selective institutioins? ✔Correct Answer-(0.09, 0.11)
What is the 95% confidence interval for the true thriving rates among graduates of private for-profit
selective institutions? ✔Correct Answer-(0.03, 0.05)
What are two things that are wrong with Statement 1? ✔Correct Answer-The statement treats the
parameter as random, and it refers nonsensically to the value of p relative to 0.