Question

In an experiment using 30 mice, the sample proportion of the mice that gained weight after a drug injection is 0.65. What is the 99.7% confidence interval for the actual proportion in the population?


A. between 0.602 and 0.697


B. between 0.563 and 0.737


C. between 0.476 and 0.824


D. between 0.389 and 0.911

Answer 1

According to your multiple choice answers you have to select from, the answer is between 0.563 and 0.737. Thank you for asking.

Answer 2

Confidence Interval for a Proportion


\[\Large L = \hat{p} + z_c*\sqrt{\frac{\hat{p}*(1-\hat{p})}{n}}\]
\[\Large U = \hat{p} - z_c*\sqrt{\frac{\hat{p}*(1-\hat{p})}{n}}\]


(L,U) is the confidence interval
L being the lower bound, U being the upper bound


\(\Large \hat{p}\) (read as "p-hat") is the sample proportion. In this case, \(\Large \hat{p} = 0.65\)
n = 30 is the sample size
\(\Large z_c\) is the critical z value (found using a calculator or a table)