The p-Value

There are a few reasons someone would determine the value of a p-value:
• The p-value is an alternate method for deciding whether or not to reject Ho (as opposed to using a rejection region)
• The p-value tells you the exact probability of selecting a sample as rare as the one you have – given that the Ho is true (the rejection region does not do this)
• It will get you the mark you need when asked to ‘calculate the p-value’