AP Stats Chapter 3 Multiple Choice Review

Front

What does the correlation coefficient (r) indicate?

Back

The correlation coefficient (r) is a number between -1 and +1 that measures the strength and direction of the linear relationship between two variables.

Front

What is the interpretation of a correlation coefficient of 0.51?

Back

A correlation coefficient of 0.51 indicates a moderate positive linear relationship between the two variables.

Front

What is the formula for calculating the residual in a regression model?

Back

Residual = Observed value - Predicted value.

Front

If George scored 80 on the first test and the regression equation is y=25+0.7x, what is his predicted final exam score?

Back

Predicted final exam score = 25 + 0.7(80) = 81.

Front

What is the residual for George if he scored 85 on the final exam?

Back

Residual = 85 - 81 = 4.

Front

What does a residual plot indicate about the fit of a linear model?

Back

A residual plot shows the differences between observed and predicted values; if the plot shows a random pattern, the linear model is a good fit.

Front

What does it mean if a correlation is affected by outliers?

Back

Outliers can significantly distort the correlation coefficient, making it misleading about the strength of the relationship.

Front

What is the least squares regression method?

Back

The least squares regression method minimizes the sum of the squares of the residuals to find the best-fitting line.

Front

What is the significance of the slope in a regression equation?

Back

The slope indicates the change in the dependent variable for a one-unit change in the independent variable.

Front

What does it mean if the correlation coefficient is close to 0?

Back

A correlation coefficient close to 0 indicates a weak or no linear relationship between the two variables.