AP Review #3: Continuous Probability (The Normal Distribution)

Using the Normal Probability Model Use the standardized score (z-score) for normally distributed variables To find the probability that x (an individual value) falls in a certain range: 1) Draw a picture 2) Find z using 3) Look up the value on the z-table to find the probability 4) Subtract if necessary 5) Look at your picture to make sure your answer makes sense!

Areas from the table Remember the table gives areas to the left If you need area to the right, subtract from 1 If you need the area between 2 z-scores, find the area to the left of each z-score first, then subtract the two areas

Sampling Distributions ( ) If the problem is asking about the average of a sample instead of an individual value of x, use Remember the Central Limit Theorem! (large sample size = normal distribution of for a random sample, even if the distribution of x is not normal) Larger sample size = smaller spread for the sampling distribution of (because as n increases, gets smaller)

Sampling Distributions ( ) If a problem asks about a sample proportion instead of a sample mean falling in a certain range, use

Use your formula sheet Remember that when you replace σ with s, or p with, in one of these formulas, it’s called the standard error