35\nselect the correct answer from each drop ...
35\nselect the correct answer from each drop - down menu\n1,200 employees of a company were surveyed to find out whether they were satisfied with the companys insurance policy. the survey showed that 80% of the respondents were not satisfied with the policy\nthe standard error of the proportion is +/- 1.15 %. the number of people who are satisfied with the policy is between % and \n\n81.15\n21.15\nreset\nnext
Answer
# Answer:
The number of people who are satisfied with the policy is between 18.85% and 21.15%.
# Explanation:
## Step1: Calculate proportion of satisfied
The proportion of not - satisfied is $p = 0.8$, so the proportion of satisfied is $\hat{p}=1 - 0.8=0.2$.
## Step2: Use standard error formula
The standard error of a proportion is $SE=\sqrt{\frac{\hat{p}(1 - \hat{p})}{n}}$. Here $n = 1200$, $\hat{p}=0.2$, so $SE=\sqrt{\frac{0.2\times(1 - 0.2)}{1200}}=\sqrt{\frac{0.2\times0.8}{1200}}=\sqrt{\frac{0.16}{1200}}\approx 0.0115$ or 1.15%.
## Step3: Calculate confidence interval bounds
For a simple case (approximate 95% confidence interval for proportion), the lower bound of the proportion of satisfied is $\hat{p}- 2\times SE=0.2-2\times0.0115 = 0.177$ or 17.7% (this part seems to be a mis - calculation in the problem setup as we are likely using a 1 - standard - error interval here). Using 1 - standard - error, the lower bound is $0.2 - 0.0115=0.1885$ or 18.85% and the upper bound is $0.2 + 0.0115=0.2115$ or 21.15%.