Answer using the steps in hypothesis testing: (10 points)

A clothing store believes that the mean income of the store's customers exceeds 30,000 per

month. One hundred fifty customers are randomly selected and asked of their annual income.

The sample mean is 30,500 and its standard deviation is 4,200. Is there sufficient evidence

to indicate that the mean household income of the customers of the store exceeds 30,000

per month. Use = 0.05.