P-Value Approach Hypothesis Testing about a Population Mean with unknown Example 5: A survey of 15 large U.S. cities finds that the average commute time one way is 25.4minutes. A chamber of commerce executive feels that the commute in his city is lessand wants to publicize this. He randomly selects 25 commuters and finds the average is 22.1 minutes with a standard deviation of 5.3 minutes. Ata - 0.01 , is there enough evidence to support the claim? Use the - value approach. (a) Setup : U= (b) Use TI-84/calculator to find . and its corresponding - value. (c) Conclusion.: = P-value ~