A catalog sales company promises to deliver orders placed on the Internet within 3 days. Followup calls to a few randomly selected customers show that a 95% confidence interval for the proportion of all orders that arrive on time is 88% ± 6% What does this mean?

Are these conclusions correct? Explain.

a) Between 82% and 94% of all orders arrive on time.

b) 95% of all random samples of customers will show that 88% of orders arrive on time.

c) 95% of all random samples of customers will show that 82% to 94% of orders arrive on time.

d) We are 95% sure that between 82% and 94% of the orders placed by the customers in this sample arrived on time.

e) On 95% of the days, between 82% and 94% of the orders will arrive on time.