Question

Adult IQ scores have a bell-shaped distribution with a mean of 100 and a standard deviation of 15. Use the Empirical Rule to find the percentage of adults with scores between 55 and 145.
1) 68%
2) 100%
3) 95%
4) 99.7%

Answer 1

What we seek is that portion of the population which is all those who score within three standard deviations of the mean. That's the vast majority, looks like 99.7%.

Answer 2

It is.