# Thread: Value of Z that corresponds to an area under the curve?

1. ## Value of Z that corresponds to an area under the curve?

What value of $Z$ corresponds to an area under the curve of $2.5$%? That is, what is Z(subscript)0.025? Answer in the back of the book says Z(subscript)0.025 = 1.96

I'm not sure how I'd go about solving these kinds of questions, any and all help is appreciated!

2. ## Re: Value of Z that corresponds to an area under the curve?

Originally Posted by youngb11
What value of $Z$ corresponds to an area under the curve of $2.5$%? That is, what is Z(subscript)0.025? Answer in the back of the book says Z(subscript)0.025 = 1.96

I'm not sure how I'd go about solving these kinds of questions, any and all help is appreciated!
You need to be more precise about what you are asking, what you have posted is meaningless.

In the standard normal distribution the area under the density curve between Z=+/- 1.96 is 0.95, ans the area under the curve beyond Z=1.96 is 0.025.

Once you have made clear what you are asking for it will just require a table look-up, exactly how depends on the exact form of your normal distribution table.

CB

3. ## Re: Value of Z that corresponds to an area under the curve?

Originally Posted by CaptainBlack
You need to be more precise about what you are asking, what you have posted is meaningless.

In the standard normal distribution the area under the density curve between Z=+/- 1.96 is 0.95, ans the area under the curve beyond Z=1.96 is 0.025.

Once you have made clear what you are asking for it will just require a table look-up, exactly how depends on the exact form of your normal distribution table.

CB
Thanks! The question in the book simply read "What value of Z corresponds to an area under the curve of 2.5%?" When you said:

the area under the curve beyond Z=1.96 is 0.025.
I assume that was what we were supposed to do. If given the area under the curve beyond a point, how would I find the Z value associated with it?