HELP please with this statistic

Question

Assume that adults have IQ scores that are normally distributed with a mean of

mu equals μ=100

and a standard deviation

sigma equals σ=20.

Find the probability that a randomly selected adult has an IQ between

80

and

120.

Answer 1

68%, use the 68-95-98 rule for percentages 1, 2 and 3 standard deviations from the mean

80 to 120 is within 1 standard deviation of 20 from the mean 100. 100-20=80 100+20=120.

Every IQ between 80 and 120 is within plus or minus one standard deviation from the mean.

or use a Z table and get a closer approximation of 68.27%

or use a scientific calculator with statistics functions that can also give you the answer