Question

The antibody production of 12 male red-winged blackbirds before and after receiving testosterone implants was compared. The units for antibody levels were natural 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 sd = 0.148 If you were assigned the task of repeating this experiment, and wanted to ensure that you could detect a mean change of 0.03 units with a probability of 0.8, then what sample size would you use? Since we are calculating n for a study of individuals, answers should be rounded up to the next whole number.

Answer 1

Answer:

I you want to ensure that you could detect a mean change of 0.03 units with a probability of 0.8, then you need at least 40 individuals for the sample.

Step-by-step explanation:

Minimum required sample size can be found using the formula

N≥$(\frac{z*s}{ME} )^2$ where

• N is the sample size

• z is the corresponding z-score for (0.8 probability) 80% confidence level (1.28)

• s is the standard deviation (0.148)

• ME (margin of error) is the margin for detecting mean change (0.03)

Using the numbers we get:

N≥$(\frac{1.28*1.48}{0.03} )^2$ ≈ 40