Question: A gardener sets up a flower stand in a busy business district and sells bouquets of assorted fresh flowers on weekdays. To find a more profitable pricing, she sells bouquets for 15 dollars each for ten days, then for 10 dollars each for five days. Her average daily profit for the two different prices are given below.
a. Construct the 90% confidence interval for the difference in the population means based on these data.
b. Test, at the 10% level of significance, whether the data provide sufficient evidence to conclude the gardener's average daily profit will be higher if the bouquets are sold at $10 each.