Refer to the National Snow and Ice Data Center (NSIDC) collection of data on the albedo, depth, and physical characteristics of ice-melt ponds in the Canadian Arctic, presented in Exercise 2.15 (p. 40). Albedo is the ratio of the light reflected by the ice to that received by it. (High albedo values give a white appearance to the ice.) Visible albedo values were recorded for a sample of 504 ice-melt ponds located in the Barrow Strait in the Canadian Arctic; these data are saved in the PONDICE file.

a. Find a 90% confidence interval for the true mean visible albedo value of all Canadian Arctic ice ponds.

b. Give both a practical and a theoretical interpretation of the interval.

c. Recall from Exercise 2.15 that the type of ice for each pond was classified as first-year ice, multiyear ice, or land fast ice. Find 90% confidence intervals for the mean visible albedo for each of the three types of ice. Interpret the intervals.