Dr. Hunt is interested in determining how his students are performing on his mid-term examination. He has administered a test to his students that attempts to measure their understanding of theory. Scores on the exam range from 1 to 10, with 1 being complete failure and 10 being excellent. Answer the following questions based upon these test scores.

10

9

9

8

8

8

7

7

6

5

What is the Mean of the above scores? What is the Median? What is the Mode?

Is this distribution Normal or Skewed? If it is skewed, then is it skewed positive or negative?

What is the Range for the above Distribution? What is the standard deviation? What is the variance?

Dr. Nylander is interested in examining the grades on an admissions test to the graduate program here at Delta State University. He has conducted his research and discovered that the data set forms a normal distribution. He has the following values:

The mean is 72 and the standard deviation is 4.5.

He is now concerned with discovering what percentage of scores are falling between +1 and +2 standard deviation units?  At -3 what is the lowest that most people should score?  At +1 what is the highest that most people should score?

Answers to Practice

Problem #1

What is the Mean of the above scores? 7.7 What is the Median? 8 What is the Mode? 8

Is this distribution Normal or Skewed? Normal If it is skewed, then is it skewed positive or negative? Not Skewed

What is the Range for the above Distribution? 5 What is the standard deviation? 1.42 What is the variance? 2.01

Problem #2

He is now concerned with discovering what percentage of scores are falling between +1 and +2 standard deviation units? 13% (13.59% if you are more precise)

At -3 what is the lowest that someone should score? 58.5 At +1 what is the highest that someone should score? 76.5