Areal estate developer is considering investing in a shopping mall on the outskirts of atlanta, georgia. three parcels of land are being evaluated. of particular importance is the income in the area surrounding the proposed mall. a random sample of four families is selected near each proposed mall. following are the sample results. at the 0.05 significance level, can the developer conclude there is a difference in the mean income

The management of a supermarket wants to adopt a new promotional policy of giving a free gift to every customer who spends more than a certain amount per visit at this supermarket. the expectation of the management is that after this promotional policy is advertised, the expenditures for all customers at this supermarket will be normally distributed with a mean of $95 and a standard deviation of $20. if the management wants to give free gifts to at most 10% of the customers, what should the amount be above which a customer would receive a free gift?