Statistics: Looking Normal

Objectives

• Students will recognize that the shape of the distribution for a single sample varies from sample to sample, even when all the samples come from the same population.
• Students will recognize that the variability in shape from sample to sample decreases as sample size increases.
• Students will recognize that larger samples from an approximately normal population will more often "look" normal than will smaller samples from the same population.

Vocabulary

• dot plot
• histogram
• normal distribution
• normal probability plot (NPP)
• population
• sample

About the Lesson

This lesson involves examining multiple samples taken from a single approximately normal population.
As a result, students will:

• Compare dot plots, histograms, and normal probability plots to determine which representation best provides information about the normality of a distribution.
• Select multiple samples of the same size to discover that not all samples from a normal population actually look normal.
• Change sample size to compare the shapes of larger samples to those of smaller samples.