Historically, the Average Time It Takes Jessica to Swim the 200

Historically, the average time it takes Jessica to swim the 200 meter butterfly is 148.4 seconds. Jessica would like to know if her average time has changed. She records her time on 50 randomly selected occasions and computes the mean to be 147.8 seconds with a standard deviation of 2.3 seconds.
Perform the appropriate test of hypothesis to determine whether Jessica's average time has changed. Use = 0.01.
Test statistic = ______________
Critical Value(s) = ______________
Conclusion: ______________
Interpretation: __________________________________________
Compute the power of the test if Jessica's actual mean swimming time is 147.3 seconds.
______________
Interpret the results.
________________________________________________________