单选题
An analyst collects the following data related to paired observations for Sample A and Sample B. Assume that both samples are drawn from normally distributed populations and that the population variances are not known.
| Paired Observation | Sample A Value | Sample B Value |
| 1 | 25 | 18 |
| 2 | 12 | 9 |
| 3 | -5 | -8 |
| 4 | 6 | 3 |
| 5 | -8 | 1 |
The t-statistic to test the hypothesis that the mean difference is equal to zero is closest to:
【正确答案】
C
【答案解析】
C is correct. First, calculate the mean difference:
Then, calculate the sample variance and the standard error of the mean difference:
Then, calculate the t-statistic:
In this case, the mean difference is 1.4. The sample variance is 36.8. The standard error of the mean difference is 2.712932. The t-statistic is 0.51605.
