Assuming that a set of test scores is normally distributed with a mean of 120 and a standard deviation of 15. The percentage of test scores less than 120 is?

Answer 1

In a normal distribution, approximately 68% of scores are within 1 standard deviation of the mean; half of these (34%) are above the mean, and the other half are below the mean.

Approximately 95% (more accurately, 95.45%) of results are within 2 standard deviations of the mean, including those 68% that are within 1 standard deviation.

The percentage of test scores less than 120 is 50%