A market researcher for the users of Apple products wants to know the proportion of people who own an Apple iPad. A survey of 600 people indicated that 86% own an iPad.

a) Find the standard deviation of the sampling distribution of the proportions?

b) How large would be the standard deviation have been if the number of people surveyed was 150 customers (assume the proportion is about the same)?

For part b, why can't I put 150 into the equation of standard deviation instead of reduce the denominator by 4?