Exercise

Exercise 2. Polling - standard error of S

Again, consider the random variable $S$, which is the total number of Democrats in your sample of 25 voters. The variable $p$ describes the proportion of Democrats in the sample, whereas $1-p$ describes the proportion of Republicans.

What is the standard error of $S$?

Instructions

50 XP

Possible Answers

$$\mbox{SE}(S) = 25 p (1-p)$$
$$\mbox{SE}(S) = \sqrt{25p}$$
$$\mbox{SE}(S) = 25(1-p)$$
$$\mbox{SE}(S) = \sqrt{25 p (1-p)}$$