Assume that adults have IQ scores that are normally distributed with a mean of 103.7 and a standard deviation of 19 find the first quartile which is the IQ score separating the bottom 25% from the top 75%. (Hint: Draw a graph.)

The first quartile is ______

 (Type an integer or decimal rounded to one decimal place as needed.) 

Assume that z-scores are normally distributed with a mean of 0 and a standard deviation of 1. If , how do you find d?

A grading scale is set up for 1000 students test scores. It is assumed that the scores are normally distributed with a mean score of 75 and a standard deviation of 15. What is the probability a student will have a score between 45 and 75

the scores on an exam are normally distributed, with a mean of 85 and a standard deviation of 5. what percent of the scores are from 85 to 95?