How would I find the percentage difference between my control group average and one of my test group averages?

Question

My control group average is 107.7

MY test roup averages are as follows:
139.1
128.3
88.0
72.7

Answer 1

Usually you use your control group as the baseline. Find the difference between your test group mean and control group mean and divide that difference by the control group mean. For each group:

(a) (139.1 - 107.7) / 107.7 = 29%

(b) (128.3 - 107.7) / 107.7 = 19%

(c) (88.0 - 107.7) / 107.7 = -18%

(d) (72.7 - 107.7) / 107.7 = -32%

Answer 2

Consider your control group average to be the "actual" value, and consider your chosen test group to be the "experimental" value.

% Difference = { |actual-experimental| / actual } x 100

ex: |107.7-139.1| = 31.4

31.4 / 107.7 = 0.29

0.29 x 100 = 29%