Market research II A market researcher for a provider of iPod accessories wants to know the proportion of customers who own cars to assess the market for a new iPod car charger. A survey of 500...

Market research II A market researcher for a provider of iPod accessories wants to know the proportion of customers who own cars to assess the market for a new iPod car charger. A survey of 500 customers indicates that 76% own cars.

 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 125 customers (assuming the proportion is about the same)?