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Chapter 11: Confidence Intervals – Large Samples
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CHAPTER 11
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Confidence Intervals
Large Samples
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You should study the topics in this chapter if you need to review
or want to learn about
Large-sample confidence intervals for a single population proportion
Large-sample confidence intervals for a single population mean
Large-sample confidence intervals for the difference between two
population proportions
Large-sample confidence intervals for the difference between two
population means
11-1 Introduction
Here we will focus on large sample confidence intervals. When a point
estimate is used to estimate the parameter of interest, it is unlikely that the
value of the point estimate will be equal to the value of the parameter. We
will however use the value of the point estimate as a standing point to help
construct an interval estimate for the parameter. We will be able to state,
with some degree of confidence that the parameter lies within the interval,
and because of this, we refer to these intervals as confidence intervals.
Typically, we consider 90 percent, 95 percent, and 99 percent confidence
interval estimates for parameters, but any other percentage can be considered.
In this chapter, we will consider large-sample confidence intervals for a
single population proportion and mean, and for the difference between two
population proportions and means.
When we speak of large samples we imply that the Central Limit Theorem
for the particular situation applies. (Please refer to Chapter 10 for a review).