Questions: Use the sample data and confidence level given below to complete parts (a) through (d).
A research institute poll asked respondents if they felt vulnerable to identity theft. In the poll, n=907 and x=600 who said "yes." Use a 99% confidence level.
a) Find the best point estimate of the population proportion p.
(Round to three decimal places as needed.)
b) Identify the value of the margin of error E.
E=
(Round to three decimal places as needed.)
c) Construct the confidence interval.
<p<
(Round to three decimal places as needed.)
d) Write a statement that correctly interprets the confidence interval. Choose the correct answer below.
A. There is a 99% chance that the true value of the population proportion will fall between the lower bound and the upper bound.
B. 99% of sample proportions will fall between the lower bound and the upper bound.
C. One has 99% confidence that the sample proportion is equal to the population proportion.
D. One has 99% confidence that the interval from the lower bound to the upper bound actually does contain the true value of the population proportion.
Transcript text: Use the sample data and confidence level given below to complete parts (a) through (d).
A research institute poll asked respondents if they felt vulnerable to identity theft. In the poll, $\mathrm{n}=907$ and $\mathrm{x}=600$ who said "yes." Use a $99 \%$ confidence level.
a) Find the best point estimate of the population proportion $p$. $\square$
(Round to three decimal places as needed.)
b) Identify the value of the margin of error $\mathbf{E}$.
$\mathrm{E}=$ $\square$
(Round to three decimal places as needed.)
c) Construct the confidence interval. $\square$
$<\mathrm{p}<\square$ $\square$
(Round to three decimal places as needed.)
d) Write a statement that correctly interprets the confidence interval. Choose the correct answer below.
A. There is a $99 \%$ chance that the true value of the population proportion will fall between the lower bound and the upper bound.
B. $99 \%$ of sample proportions will fall between the lower bound and the upper bound.
C. One has $99 \%$ confidence that the sample proportion is equal to the population proportion.
D. One has $99 \%$ confidence that the interval from the lower bound to the upper bound actually does contain the true value of the population proportion.
Solution
Solution Steps
Step 1: Calculate the Sample Proportion
Using the formula \(\hat{p} = \frac{X}{n}\), where \(X=600\) and \(n=907\), we find \(\hat{p} = 0.662\).
Step 2: Find the Z-score
The Z-score corresponding to the desired confidence level is given as \(Z=2.576\).
Step 3: Calculate the Standard Error of the Proportion
Using the formula \(SE = \sqrt{\hat{p}(1-\hat{p})/n}\), we find \(SE = 0.016\).
Step 4: Calculate the Margin of Error
Using the formula \(E = Z \times SE\), with \(Z=2.576\), we find \(E = 0.04\).
Step 5: Construct the Confidence Interval
The confidence interval for the population proportion \(p\) is calculated as \(\hat{p} \pm E\), which gives us (0.621, 0.702).
Final Answer:
We are confident that the true population proportion \(p\) lies within the interval (0.621, 0.702).