Question

Some IQ scores are standardized with a mean of 100 and a standard deviation of 16. Using the 68-95-99.7 Rule, Determine: 1. What percent of people would have an IQ score of no more than 68. (2).What percent of people would have an IQ score of 100 or above.

Answer 1

1. 68 is 2 sigma from the mean. 95% are within that distance of the mean, and 5% are outside it. Half of those (2.5%) are below it on the low side (below 68).

2. 50%. The mean always divides the distribution in that ratio: half above and half below.