Question

Suppose you and another student are working on the normal distributio n problem together. You are asked to find the probability a man’s blood pressure is over 132. Your friend draws the distribution and shades in the region above 132 (like the picture to the right). Then they state the answer is 0.88493. However, this is the wrong answer. How do you know? What went wrong? What is the correct answer?

Answer 1

In the absence of actual data(i.e. Mean and S.D.), we can't exactly tell the probability figures, but we'll use the given figures to derive everything.

It is clearly visible in the graph that 132 lies to the right of the mean of the distribution. Hence, clearly, probability of something more than that of a point in the right of the mean can not exceed 0.5.

Hence, we are quite sure that the answer for more than 132 can't be 0.88493.

He took the left of the distribution while calculating.

We can make it right by taking the right side, i.e.

I hope this solves your doubt.

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