Can anyone help with this question I think the answer is 13

In a normally-distributed variable measured at the interval/ratio level, approximately what portion of scores fall between the mean and one standard deviation below the mean?

Solution

By empirical rule, 68% lie within one standard deviation from the mean, but this is both below and above the mean.

Thus, only below the mean, 68%/2 = 34% lie, which is closest to 1/3. [ANSWER, OPTION C]