Answer:
Mean of 64 and standard error of 0.9.
Step-by-step explanation:
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean
and standard deviation
, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean
and standard deviation
.
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
Phone bills from the residents of the city have a mean of $64 and a standard deviation of $9. Sample of 10.
By the Central Limit Theorem, the mean is 64 and the standard error is
So mean of 64 and standard error of 0.9.