Normal distribution, hypothesis, z-score

Hi

Got this excersize for my assignment and not even know where to start, try resurch and watch some videos. Still a big mess for me. is it possible somebody can give me some advice what to do and how? I would like understand whats going on and how I need to write this kind of script.

Task:

Exercise 4.

The time in minutes, T, taken to construct a piece of furniture can be described by a normal distribution where T∈N(21,49).

Calculate the probability that when timed, a person completes the construction between 22 and 28 minutes. In addition, calculate the probability that completion will occur within 30 seconds of the mean time. You should complete this analysis using the z-score as well as MatLab functions within a well commented MatLab script.

Many thanks for the help