Exercise

Exercise 3. Polling - expected value of X-bar

Consider the random variable $S/N$, which is equivalent to the sample average that we have been denoting as $\bar{X}$. The variable $N$ represents the sample size and $p$ is the proportion of Democrats in the population.

What is the expected value of $\bar{X}$?

Instructions

50 XP

Possible Answers

$$ \mbox{E}(\bar{X}) = p $$
$$ \mbox{E}(\bar{X}) = Np $$
$$ \mbox{E}(\bar{X}) = N(1-p)$$
$$ \mbox{E}(\bar{X}) = 1-p $$