| Video 20 |
| Significance Tests |
| This program explains the basic reasoning behind tests of significance and the concept of null hypothesis. The program shows how a z-test is carried out when the hypothesis concerns the mean of a normal population with known standard deviation. These ideas are explored by determining whether a poem “fits Shakespeare as well as Shakespeare fits Shakespeare.” Court battles over discrimination in hiring provide additional illustration. |
| Video 21 |
| Inference for One Mean |
| In this program, students discover an improved technique for statistical problems that involve a population mean: the t statistic for use when σ is not known. Emphasis is on paired samples and the t confidence test and interval. The program covers the precautions associated with these robust t procedures, along with their distribution characteristics and broad applications. |
| Video 22 |
| Comparing Two Means |
| How to recognize a two-sample problem and how to distinguish such problems from one- and paired-sample situations are the subject of this program. A confidence interval is given for the difference between two means, using the two-sample t statistic with conservative degrees of freedom. |
| Video 23 |
| Inference for Proportions |
| This program marks a transition in the series: from a focus on inference about the mean of a population to exploring inferences about a different kind of parameter, the proportion or percent of a population that has a certain characteristic. Students will observe the use of confidence intervals and tests for comparing proportions applied in government estimates of unemployment rates. |