| MA 117 Probability and Statistics Math - Block 4 - 2001 |
| Reading in preparation for Friday, Week Two: |
| Chapter Twenty One | |
| Read through the dialogue in chapter 21, page 376, and the rest of section 1. |
1. Why should the politician care about the standard error? If the politician is favoured in the sample, why doesn’t that automatically mean the politician will win the election? 2. In the example on page 378, the sample percentage is 79%. Why is this not the expected value for the sample? |
| Read through section 2 on confidence intervals, starting on page 381. |
3. Why does a larger confidence level require a larger interval? 4. Why does a smaller interval correspond to a lower confidence level? |
| Read through section 3 on interpreting confidence intervals, starting on page 384. |
5. Suppose the 100 confidence intervals in figure 1 were made into 99% confidence intervals.
6. Why does a smaller interval correspond to a lower confidence level? |
| Read through sections 4 and 5 on surveys which are not simple random samples, starting on page 390. |
7. Is the error in the Gallup poll larger or smaller than simple random sampling predictions? 8. What are two of the reasons for the differences between the Gallup poll errors and simple random sampling errors? |
| Chapter Twenty Three | |
| Read through section 1 starting on page 409. |
1. Read through example 1 and notice the histogram for the sum of the draws at the top of figure 1. Check that the calculated SE (for the sum) captures about 68% of the samples within one SE of the EV (for the sum). Notice the similarity of the second histogram, which is just a change of scale to show the average. 2. Do example 1 in set A |
| Read section 2, which begins on p. 415 | 3. In the example 3 on page 417, why is the sample average of 11.6 not the sample average? |
| Read through sections 3 and 4. | 4. Make an example situation for each of the four standard errors mentioned on p. 422. |