AP Statistics
posted by Alex .
Hi, we just started density curves in AP Stats, and I am a little confused about one of the concepts.
It keeps saying that a density curve has to have an area equal to 1 below it...
1 of what?
I don't understand how you figure out if the area of your curve is 1, or what unit this "1" is in...
Sorry, and thanks!

If you understand that density curves are eventually used for calculating probabilities of certain events, they have to be normalized some how. Since the total area under the density represent the probability of all possible events, it would be convenient to normalize the area to unity.

A density curve is just another way of saying a pie chart. Its 100%, a whole. which is alonther word for saying its equal to 1. your different measurements with be equal to different percentages that you will mark in the density curv. All of them comprised will equal t. so for example..a measurement will be 60% of people. you will shade .60 and be left with .40. Together they will equal 1.
make sense? 
Yes, I think so. Thanks :)