Statistics: Normal Probability Plot

Objectives

• Students will identify the shape of a distribution as being skewed or mound-shaped and approximately symmetric.
• Students will recognize that a normal probability plot of skewed data is nonlinear and either concave up or concave down.
• Students will recognize that a normal probability plot of approximately normal data is approximately linear.
• Students will identify outliers on a normal probability plot.

Vocabulary

• normal
• normal probability plot
• outlier
• skew
• symmetric

About the Lesson

This lesson involves creating a normal probability plot for several data sets involving height to examine the appearance of such plots when the distribution is approximately normal.
As a result, students will:

• Use a histogram to discuss the shape of the distribution of a data set.
• Describe a normal probability plot for data sets whose distributions are skewed, approximately normal, or contain outliers.
• Move data values in a dot plot to investigate how the shape of a distribution compares to the linearity of a normal probability plot.