The grades of 1,000 students, ranging from 1 to 100, are normally distributed with a mean of 50.

I’m having a hard time understanding why the answer to this question is B. Would be helpful if someone could provide the rationale behind it.

The grades of 1,000 students, ranging from 1 to 100, are normally distributed with a mean of 50.

I’m having a hard time understanding why the answer to this question is B. Would be helpful if someone could provide the rationale behind it.

Draw the normal distribution curve

Plot the points

Now, shade the region with common area and compare what is left.