Use the 5-step procedure to create the confidence intervals in #1 & #4. A Pew Re
ID: 3063958 • Letter: U
Question
Use the 5-step procedure to create the confidence intervals in #1 & #4.
A Pew Research Center poll included 1708 randomly selected adults who were asked whether “global warming is a problem that requires immediate government action.” Results showed that 939 of those surveyed indicated that immediate government action is required.
1) Construct a 99% Confidence Interval to estimate the proportion of adults believing that immediate government action is required.
Work this problem by hand without using the CI function in StatCrunch or on the graphing calculator.
2) Is there strong evidence supporting the claim that the majority (> 50%) is in favor of immediate government action? Explain your answer.
3) As a newly hired manager of a company that provides cell phone service, you want to determine the percentage of adults in your state who live in a household with cell phones and no land-line phones. How many adults must you survey? Assume that you want to be 90% confident that the sample percentage is within 4 percentage points of the true population percentage.
In a test of effectiveness of garlic for lowering cholesterol, 47 subjects were treated with Garlicin, which is garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes in their levels of LDL cholesterol (in mg/dL) have a mean of 3.2 and a standard deviation of 18.6.
4) Construct a 95% confidence interval to estimate the mean net change in LDL cholesterol after the garlic treatment.
You can use technology for this problem.
5) If we want to construct a 99% confidence interval from this information, WITHOUT actually calculating the interval, would it be smaller or larger than the one calculate din #4? Explain your answer.
Explanation / Answer
answering 1) as per chegg policies
1)
p +- z(a/2)*sqrt(p*(1-p)/n)
z(a/2)= 2.576
lower= =0.55-2.576*SQRT(0.55*(1-0.55)/1708) = 0.519
upper= =0.55+2.576*SQRT(0.55*(1-0.55)/1708) = 0.581
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