The bar graph shows the recommended number of hours of sleep for each age group. How many hours of sleep are recommended for elementary-age children?
A. exactly 9 hours
B. exactly 10 hours
C. about 10 hours
D. about 12 hours

Assume that adults have iq scores that are normally distributed with a mean of mu equals 100 and a standard deviation sigma equals 20. find the probability that a randomly selected adult has an iq between 80 and 120.assume that adults have iq scores that are normally distributed with a mean of mu equals 100 and a standard deviation sigma equals 20. find the probability that a randomly selected adult has an iq between 80 and 120.