40 people are randomly sent to walk one of four trails. The time (in minutes) they spend completing each trail is recorded in the table below. (a) Test to see if the times needed to complete a trail...

40 people are randomly sent to walk one of four trails. The time (in minutes) they spend completing each trail is recorded in the table below.

(a) Test to see if the times needed to complete a trail vary. Use a 0.05 significance level.

(b) Test each pair (A/B, A/C, A/D, B/C, B/D, C/D) to see which trails have a statistically significant difference. Indicate your p-value for each comparison, and when the effect is statistically significant (use 0.05 as your significance level), declare which trail of the two takes more time to complete.

Trail A - 30, 33, 41, 27, 36, 31, 37, 40, 29, 35

Trail B - 27, 33, 38, 41, 40, 38, 35, 44, 41, 39

Trail C - 25, 34, 41, 39, 32, 30, 36, 35, 27, 33

Trail D - 41, 39, 46, 37, 40, 42, 50, 42, 50, 33, 47, 43