Here is the problem:

(A) Select a random sample of 30 student from our population (we have a data entry to get the sample from). At the 0.05 level of significance is there evidence that the average travel time is greater than 45 minutes?

(B) What assumptions must hold in order to perform the test in (A)?

(C) Evaluate the assumption in (B) through a graphical approach. Are the results valid? Discuss.

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Part (A) is the one I need the most help with,but more help is always welcome
I'm not sure which formula to use, am I using the null hypothesis? Z-test? I'm SO confused. What is the procedure for solving this?
THANKS SO MUCH IN ADVANCE FOR ANY HELP!