Question

A study of the effects of exercise used rats bred to have high or low capacity for exercise. The 8 high-capacity rats had mean blood pressure 89 mm Hg and standard deviation 9 mm Hg; the 8 low-capacity rats had mean blood pressure 105 mm Hg with standard deviation 13 mm Hg. What is the value of the two-sample t statistic for comparing the two population means?

Answer 1

Since nothing is mentioned about the differencing,i.e,whether it should be between high or low or between low or high, the problem is solved by taking the difference between the high capacity rats and the low capacity rats. If the other case is required,i.e,the difference between low capacity and the high capacity rats,then the value of the test statistic would be positive and the rest procedure remains same.

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