AP Statistics Interpretation Guide

Important interpretations to know for AP Statistics Exam

Describe the distribution…

Center, Unusual Features, Shape, Spread

Describe the association…

There is a [weak, moderate, strong], [positive, negative], [linear, nonlinear] association between…

Interpret the r value

There is a [weak, moderate, strong], [positive, negative], [linear, nonlinear] association between…

Interpret the coefficient of determination (R²)

____% of the variation in [y variable] is explained by its linear relationship with [x variable]

Observational study or experiment?

Experiments have random assignments of the treatments, which allow us to establish causation. Observational studies do NOT have random assignment.

Interpret the slope

For every 1 increase in [v variable], our [y-variable] is predicted to increase/decrease by _____.

Interpret the y intercept

If the [x variable] is 0, we predict that the [y variable] will be ____.

Interpret S from computer output

Standard deviation of the residuals. Predicted error from using our linear regression model.q

Concluding hypothesis test from p-value

Since p<0.05, we reject the Ho. We have significant evidence that …..

OR

Since p>0.05, we fail to reject the Ho. We do not have significant evidence that…

Interpret p value.

Assuming that Ho is true, we have a ___ probability of observing a sample mean/proportion as extreme or more extreme as ours.

Interpret z score

The number of standard deviations above or below the mean.

Interpret Standard Deviation

The average distance from the mean.

Interpreting confidence INTERVAL

We are ___% confident that the true mean/proportion of ______ is between ____ and ____.

Interpreting confidence LEVEL

If we were to create many many unique random samples of that given size, approximately ____% of them would contain the true parameter (mean or proportion).

Equation for Least Squared regression line

Avoid using only y and x, use words that pertain to context.

predicted y in context = a + b (x in context)