## Answer :

**Answer:**

In mathematical form, you can represent the critical value for a 90% confidence level with a sample size of 25 as:

**Step-by-step explanation:**

\[ Z_{\alpha/2} = 1.645 \]

Where:

- \( Z_{\alpha/2} \) is the critical Z-value for a two-tailed test at a significance level of \( \alpha/2 \) (where \( \alpha = 0.10 \) for a 90% confidence level).

- The critical value \( Z_{\alpha/2} \) is approximately 1.645.