Question

Iq scores can be described using a normal distribution with a mean of 100 and a standard deviation of 15. using the empirical '68-95-99.7' rule, what percent of iq scores are above 130?

Answer 1

130 is 2 standard deviations above the mean.

95% of the population lie within 2 standard deviations, so 5% lie outside 2 standard deviations.

The percentage lying above 2 standard deviations is half of that, so 2.5%.

Answer 2

130 is 2 standard deviations above the mean so that is equivalent to 95%. So percent above 130 =  5%.