When do I use the standardising normal distribution?

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! :slight_smile:

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!