I developed an achievement test and normalized it on people throughout the country over a year. My test has scores that are normally distributed with...

I developed an achievement test and normalized it on people throughout the country over a year. My test has scores that are normally distributed with a mean of 100 and a standard deviation of 10.

a.      Find the probability that a randomly selected adult has IQ < 115

b.     Find the probability that a randomly selected adult has IQ > 70

c.      Find P30, which is the IQ separating the bottom 30% from the top 70%

d.     What percentage of adults have scores between 90 and 110?