Question 1200091
**1. Understand the Wilcoxon Signed-Rank Test**

* The Wilcoxon Signed-Rank test is a non-parametric statistical hypothesis test used to compare two related samples. 
* It's used when the assumptions of a paired t-test (such as normality of the differences) are not met.
* It ranks the absolute differences between the paired observations and then considers the signs of the differences.

**2. Determine Critical Value (One-Tailed Test)**

* For a one-tailed test with n = 20 and significance level α = 0.05, you would typically use a table of critical values for the Wilcoxon Signed-Rank test. 
* **Find the critical value for a one-tailed test with α = 0.05 and n = 20 in the table.**

**3. Decision Rule**

* **Reject the null hypothesis (H0)** if the calculated test statistic (the sum of the ranks of the positive differences) is greater than or equal to the critical value from the table.

**Note:**

* The exact critical value will depend on the specific table you are using. 
* Some tables might provide critical values for the sum of the ranks of positive differences, while others might provide critical values for the sum of the ranks of all differences.

**To find the exact critical value:**

1. **Refer to a statistical table for the Wilcoxon Signed-Rank test.** 
2. **Look for the table that corresponds to a one-tailed test with α = 0.05.**
3. **Find the row for n = 20.**
4. **Read the critical value from the table.**

**Example:**

* If the table provides critical values for the sum of the ranks of positive differences:
    * The critical value might be something like 60. 

* If the table provides critical values for the sum of the ranks of all differences:
    * The critical value might be something like 110.

**Remember to use the correct table and interpretation based on the specific table you are referencing.**