Questions 1 and 2

1) You measure the height of 11 oak trees and 9 maple trees. Is there a difference in height? Use a Mann- Whitney U test (do NOT use R): Oak trees: 55 74 60 29 37 106 63 57 50 68 110 Maple trees: 70 98 96 68 86 108 86 86 100 Note: this should be two sided - why?? 2) Now read the following data into R. Use R for all statistical procedures. Sample Sample A B 0. 7969 1. 4731 1. 2669 3.2137 1 . 5856 2.2486 0. 4959 1. 1156 0 . 5022 10. 6207 0 . 5524 1. 9835 10.3060 31. 2243 0 . 6244 3. 7984 1. 9789 1 . 4710 1 . 6788 9. 0351 (a) Make q-q plots of both samples. (b) Perform a t-test (Welch's test). (c) Perform a MWU test. (d) Which test gave you the better p-value now? Why? (e) What is a "better" p-value? Why? (f) This is two sided - why