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# Random Sampling and Estimation

## Learn how to select a random sample and use it to estimate characteristics of an entire population. Learn how to describe variation in estimates, and the effect of sample size on an estimate's accuracy.

In This Session
Part A:
Random Samples
Part B:
Selecting the Sample
Part C:
Investigating Variation in Estimates
Part D:
The Effect of Sample Size
Homework

In this session, you will learn how to use results from a random sample to estimate characteristics of an entire population. To predict the accuracy of your estimates, you will investigate the variation in estimates based on repeated random samples from that population. See Note 1 below.

Learning Objectives
In this session, you will estimate population quantities from a random sample. You will learn how to do the following:
• Define an estimate based on sample data
• Select a random sample
• Describe sample-to-sample variation
• Predict the accuracy of an estimate
• Assess the effect of sample size on the accuracy of an estimate

### Key Terms

Previously Introduced:

New in This Session:

### Notes

Note 1
This session considers the use of random sampling for estimating characteristics of an entire population. Random sampling leads to random variation in estimates, and this variation can be described by a probability distribution. The normal curve approximation, which some statistics learners may be familiar with, is described only briefly. A stem and leaf plot of typical results of independent sample estimates is used for the investigations, which removes a level of abstraction from the description of sampling concepts.