Critical Values > Area Under a Normal Distribution Curve

## How To Find the Area Under a Normal Distribution Curve

How you find the area under a normal distribution curve depends on what your shaded area looks like. Before you can solve for the area under a normal distribution curve, you must be able to imagine what you area looks like. The best (albeit optional) way to imagine this is to make a sketch. For example, let’s say you were give a z-score and were asked to find the area between that score and z=0 (the mean). Your sketch might look like this:

There are seven ways your sketch could look, depending on what values you were given. **Once you have drawn your sketch, look at the pictures below**. Click on the image that looks like your sketch. the link will take you to a step-by-step guide on how to find the area under a normal distribution curve for that shape. Many of these also have short videos showing the steps.

## Choose One

**Tip:** Drawing sketches in probability and statistics isn’t just limited to normal distribution curves. If you get used to making a sketch, you’ll also have an easier time with creating complicated graphs (like contingency tables).

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I bought your book but I’m not sure where to look for the following step-by-step problem solver. I’m on chapter 8 sections 8.1 & 8.2(Statistics Informed Decisions Using Data, M. Sullivan, III). I can solve part a) to the questions but then get lost (my answers aren’t matching the text answers). Here is an example: 8.2 #17 b)What is the probability that in a random sample of 500 adult Americans less than 38% believe that marriage is obsolete? (Note: 39% is the ‘mean’ or P; p-hat?) The text answer is P(‘p hat’ < 0.38)=0.3228 [Tech: 0.3233]* (*I'm allowed to use my TI-84plus calculator too).

where do I look in my 'Practically Cheating Handbook'? Please guide me. I'm hoping you can help (soon). Thanks!

It looks like this problem is using the z-table or t-table. Does the question give you the standard deviation?

Hi..

how to find the area of p (0<z<0.855)

I can be able to find 0.85 only. How to find for 0.005. Pls help me

It would be in between 0.85 and 0.86.