1. **State the problem:** We want to test if there is overwhelming evidence to contradict the supervisor's claim that the average assembly time is 50 minutes. 2. **Set up hypotheses:** - Null hypothesis $H_0$: $\mu = 50$ - Alternative hypothesis $H_a$: $\mu \neq 50$ (two-tailed test) 3. **Given data:** - Population mean under $H_0$: $\mu_0 = 50$ - Sample mean: $\bar{x} = 55$ - Population standard deviation: $\sigma = 13$ - Sample size: $n = 28$ - Significance level: $\alpha = 0.01$ 4. **Formula for test statistic (Z):** $$Z = \frac{\bar{x} - \mu_0}{\sigma / \sqrt{n}}$$ 5. **Calculate the standard error:** $$SE = \frac{13}{\sqrt{28}} \approx \frac{13}{5.2915} \approx 2.456$$ 6. **Calculate the test statistic:** $$Z = \frac{55 - 50}{2.456} = \frac{5}{2.456} \approx 2.04$$ 7. **Interpretation:** The test statistic value is approximately $2.04$. This completes Step 2: computing the test statistic value.