In a Singapore edition of Business Times, diamond pricing was explored. The price of a diamond is based on the diamond’s weight, color, and clarity. A simple random sample of 18 one-half-carat diamonds had the following prices, in dollars.

a. Apply the t-interval procedure to these data to find a 90% confidence interval for the mean price of all one-half-carat diamonds. Interpret your result.

b. Obtain a normal probability plot, a boxplot, a histogram, and a stem-and-leaf diagram of the data.

c. Based on your graphs from part (b), is it reasonable to apply the t-interval procedure as you did in part (a)? Explain your answer.