A student of the author weighed a simple random sample of Porterhouse steaks, and the results (in ounces) are listed below. The steaks are supposed to be 21 oz because they are listed on the menu as weighing 20 ounces, and they lose an ounce when cooked. Use the listed weights to find the (a) mean; (b) median; (c) mode; (d) midrange; (e) range; (f) standard deviation; (g) variance; (h) Q₁; (i) Q₃.

17 19 21 18 20 18 19 20 20 21