Hello! I don’t understand when we’re supposed to standardise the normal distribution( make the mean = 0 and standard deviation = 1.) How do we know what questions to use this with in the exam?
(sorry if I formatted this wrong this is my first time using this)
Thanks in advance!!
Welcome to the forum! 
In some questions you need to find Z. You can always use the Standard Normal Distribution table for that. But if you would like to use a calculator and your questions doesn’t give you Standard deviation or mean then you just type SD=1 and mean=0 to find it.
Look at the formula for Z:
If you substitute mean=0 and SD=1 then Z=x so value of x on the calculator will be Z for your question. However, if you are confident using the the table just stick with it.
Good luck!