In a large population of US cell phone owners, the mean number of contacts is 112 with a standard deviation of 20. Suppose 200 cell phone owners are randomly selected for a market research campaign. What is the shape of the sampling distribution of the sample mean number of contacts?
- Approximately Normal, because the sample size is greater than 30.
- We cannot say, because 200 cell phone owners is less than 10% of the population.
- We cannot say, because the sample size is greater than 30.
- Approximately Normal, because it is reasonable to assume that this population is Normally distributed.
- Approximately Normal, because 200 cell phone owners is less than 10% of the population.