Question

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Answer 1

Answer:

a. 2,727

b. (85.6%, 87.6%)

Step-by-step explanation:

The percentage of the adults aged 57 through 85 that used at least one prescription medication = 86.6%

a. The expected number of the 3,149 subjects aged 57 through 85 that used at least one prescription medication = 3,149 × 86.6/100 = 2,727.034 ≈ 2,727 (subjects)

b. The 90% confidence interval estimate of the percentage of adults aged 57 through 85 years who use at least one prescription medication is given as follows;

$CI=\hat{p}\pm z\times \sqrt{\dfrac{\hat{p} \cdot (1-\hat{p})}{n}}$

Where;

$\hat p$ = 86.6/100= 0.866

n = 3,149

z = The z-value at 90% confidence level = 1.645

Therefore, we get the following confidence interval of the percentage of adults (rounded to one decimal place as required);

$\left (0.866 - 1.645\times \sqrt{\dfrac{0.866 \times (1-0.866)}{3,149}}\right) \times 100 \% \approx 85.6 \%$

$\left( 0.866 + 1.645\times \sqrt{\dfrac{0.866 \times (1-0.866)}{3,149}} \right) \times 100 \% \approx 87.6 \%$

The 90% confidence interval, of the percentage C.I. ≈ (85.6%, 87.6%).