文档介绍：Chapter 20—Confidence Intervals, Part 1: Assessing the Accuracy of Samples 307
CHAPTER
Confidence Intervals,
Part 1: Assessing the
20 Accuracy of Samples
Introduction
Estimating the Accuracy of a Sample Mean
The Logic of Confidence Intervals
Computing Confidence Intervals
Procedure for Estimating Confidence Intervals
Introduction
This chapter discusses how to assess the accuracy of a point
estimate of the mean, median, or other statistic of a sample.
We want to know: How close is our estimate of (say) the sample
mean likely to be to the population mean? The chapter begins
with an intuitive discussion of the relationship between a) a
statistic derived from sample data, and b) a parameter of a
universe from which the sample is drawn. Then we discuss
the actual construction of confidence intervals using two dif-
ferent approaches which produce the same numbers though
they have different logic. The following chapter shows illus-
trations of these procedures.
The accuracy of an estimate is a hard intellectual nut to crack,
so hard that for hundreds of years statisticians and scientists
wrestled with the problem with little ess; it was not until
the last century or two that much progress was made. The ker-
nel of the problem is learning the extent of the variation in the
population. But whereas the sample mean can be used straight-
forw