How does the result in Prob. 6 change if we use a smaller sample, say, of size 5, the other data (x̅ = 58.05, α = 5%, etc.) remaining as before?

Data from Prob. 6

Assuming normality and known variance σ² = 9, test the hypothesis μ = 60.0 against the alternative μ = 57.0 using a sample of size 20 with mean x̅ = 58.50 and choosing α = 5%.