For questions 1-6, refer to the following information:Early in the HIV epidemic, there was poor knowledge of HIV transmission risks among health care staff. Researchers developed a short training to improve knowledge and attitudes around HIV. The knowledge scores were calculated for each participant (1) before and (2) after the training and recorded in the table below. The sample standard deviation of the differences between the scores before and after the training is 3.7786. Using a 0.05 significance level, you need to test the claim that the training was effective in improving knowledge (i.e., that the knowledge scores are higher after the training). To do so, answer each of the following questions.

Pre training score (1)	17	17	15	19	18	14	27	20	12	21
Post training score (2)	22	21	21	26	20	14	31	18	22	20

1. What is the most appropriate statistical test for the given claim? (0.5 points)

1. Wilcoxon rank-sum test
2. Two-sample z-test
3. Paired t-test
4. Two-sample (pooled variance) t-test
5. Two-sample (unpooled variance) t-test

1. What is the null hypothesis H₀? (1 point)

1.