The experiment described in Example 122 compared antibody pr

The experiment described in Example 12.2 compared antibody production in 13 male red-winged blackbirds before and after testosterone implants. The units of antibody levels were log 10^-3 optical density per minute (ln[mOD/min]). The mean change in antibody production was d = 0.056, and the standard deviation was s_d = 0.159. If you were assigned the task of repeating this experiment to test the hypothesis that testosterone changed antibody levels, what sample size (i.e., number of blackbirds) would you plan to ensure that a mean change of 0.05 units could be detected with probability 0.8? Explain the steps you took to determine this value.

Solution