Answer:
10
Explanation:
As it could be inferred from the name, repeated measure design may be explained as experimental measures involving multiple (more than one) measures of a variable on the same observation, subject or participants which are taken at either various times or periodic intervals, different levels, different conditions. Hence, a repeated measurement taken with the same sample but under different treatment conditions. Therefore, since the measurement will be performed on a the same subjects(paired) , then the number of subjects needed will be 10. As it is this same samples that will be used for the other levels or conditions.