Jamal suspects that his diastolic blood pressure is higher w

Jamal suspects that his diastolic blood pressure is higher when he is at work than his diastolic blood pressure when he is not at work. He is going to test this statement based on blood pressure readings at randomly selected times in the above two situations.

Why should we not use the two sample t-test in this case?

Use the Wilcoxon Rank Sum test with normal approximation to test if the BP readings at work are higher than the readings when not at work. Write the P_value and your conclusion at 5% level of significance.

Here are the data (units in mmHg)

at work

84 84 86   86   87   87   87   88   90   97   99

   not at work

    77   78   79   79   80   83   84   85   85   89

Solution