題組內容
2. A researcher wishes to try three different techniques to lower the blood pressure of individual diagnosed with high blood pressure. The subjects are randomly assigned to three groups. The first group takes medication, the second group exercises, and the third group follows a special diet. After four weeks, the reduction in each person's blood pressure is recorded. Assume the blood pressure reduction at each population is normally distributed and that the population variances are equal.
(1) Find the within-group variance. (5%)