Assignment 8

Normal Curve

1. Given a normal distribution with a mean of 75 and a standard deviation of 20, find the z score for the following scores.

a) 80

b) 40

2. Consider the following z scores. Use the standard normal table and provide the appropriate proportion.

a) Find the area between the mean and a z score of 1.3.

b) Find the area beyond a z score of 2.96

c) Find the area below a z score of 1.55

3. Assume a normal distribution with a mean of 30 and a standard deviation of 8.

a) Find the proportion of area between the mean and a score of 15.

b) Find the proportion of the area above a score of 11.

c) Find the proportion of the area between 20 and 35.

4. Consider the exam results that approximate a normal curve with a mean of 70 and a standard deviation of 15. You got a 75 on the exam and your friend got a 80. Find the proportion of students between your score and your friend’s score.