What is the test statistic for this test? = -2.52

What are the critical values for this test

b) Using the six-step critical value approach, at the 0.05 level of significance, is there evidence that the population mean delivery time has been reduced below the previous population mean value of 30 minutes?

c) At the 0.05 level of significance, use the five-step p-value approach.

d) Interpret the meaning of the p-value in (b).