Statistics and Probability / Choosing Random Samples

Understanding

Numbers used in describing a characteristic of the population (typically measures of center, spread, maximum and minimum) can be estimated by calculating the corresponding statistic using the data in the sample.

What to look for

To understand how a sampling process works, students need to understand the difference between a population (the large set of interest) and a sample (a subset of that population).

Sample Assessment

A survey given to some of the people at the mall on Friday night indicated that shopping hours at the mall should be extended. What is the population for this sample?

Answer:
People who were shopping at the mall on that Friday night.

The Big Idea

A random sample is a sample in which every possible subset of the population has equal chance of being selected. There are many ways to generate random samples such as: drawing names from a hat, generating random numbers, etc.

What are the students doing?

Students explore different processes generating random samples from a population.

What is the teacher doing?

Collect responses from the class in a dot plot or a frequency tally to see the distribution of the mean word lengths from the classes samples.