A marketing researcher for a phone company surveys 100 people and finds that the proportion of customers

Question:

A marketing researcher for a phone company surveys 100 people and finds that the proportion of customers who are likely to switch providers when their contract expires is 15%.
a) What is the standard deviation of the sampling of the proportion?
b) If she wants to reduce the standard deviation by half, how large a sample would she need?
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...