A random sample of 250 commuting employees found that why spend an average of $2000 a month on gas. Suppose we know the standard deviation of the underlying population to be $300. Find the mean and standard deviation of the sampling distribution of the sample mean
In a random sample of 120 iPhone users, 45 reported that they had shopped online in the past week. Find the mean and the standard deviation of the sampling distribution of the sample proportion.