The distribution of I.Q. scores can be modeled by a normal distribution with mean and standard deviation . An interactive graph of this distribution is given below. To use it, click and drag the red dot. (Be patient -- the interactive applet may take a minute to load.)
What is the formula for the density function of I.Q. scores?
Use the interactive graph to estimate the fraction of the population with I.Q. between 75 and 120.
You can earn partial credit on this problem.