Hi here is the question:

It is known that a hospital has a mean waiting time of 4 hours for its Accident and Emergency (A&E) patients. After some new initiatives were introduced, a random sample of 12 patients from the hospital's A&E Department had the following waiting times, in hours. 4.25 3.90 4.15 3.95 4.20 4.15 5.00 3.85 4.25 4.05 3.80 3.95 Carry out a hypothesis test at the 10% significance level to investigate whether the mean waiting time at this hospital's A&E department has changed. You may assume that the waiting times are normally distributed with standard deviation 0.8 hours.

I want to know how I would solve this thank you