A market researcher for a provider of cell phone accessories wants to know the proportion of customers who own cars to assess the market for a new cell phone car charger. A survey of

400 customers indicates that 74% own cars.

ROUND TO FOUR DECIMAL PLACES

a) What is the standard deviation of the sampling distribution of the proportion?

b) How large would the standard deviation have been if he had surveyed only

100 customers (assuming the proportion is about the same)