CHAPTER 6 Estimation Chapter Outline 6.1 Estimating the Population Mean 164 6.2 Sampling Error 165 6.3 The Sampling Distribution of the Sample Mean The Shape of the Distribution Unbiased Estimators 167 Sampling Variance 169 Putting It All Together 169 Confidence Intervals 171 166 166 6.4 The t Distribution 172 6.5 Conf idence Inter vals Using the t Distribution Do Not Forget the Square Root of the Sample Size Choosing a Conf idence Level 177 Choosing a Sample Size 177 Sampling from Finite Populations 178 174 176 Exercises 179 While the individual man is an insolvable puzzle, in the aggregate he becomes a mathematical certainty. You can, for example, never foretell what any one man will do,