The amounts of electric bills for all households in a city have an approximately normal distribution with a mean of $110 and a standard deviation of $20. Let x-bar be the mean amount of electric bills for a random sample of 16 households selected from the city.
(a) Compute the mean, of x-bar.
$______
(b) Compute the standard deviation, of x-bar.
$______
(c) Comment on the shape of the sampling distribution of x-bar:
Uniform, normal, or hypergeometric