13 (0.5 points) Regression analysis is used to: Question 13 options: Estimate sample size needs when planning a study that involves correlation Determine the mean difference between two groups Determine the magnitude of effects of correlations among variables Make predictions about the values of a variable based on known values of another variable Question 14 (0.5 points) In regression analysis, residuals refer to Question 14 options: Predicted values The term (Y - Y')2 Standard error of estimate Errors of prediction Question 15 (0.5 points) What is an intercept? Question 15 options: The "b" part of the equation for a straight line The "x" part of the equation for a straight line The angle of a straight line The point where a straight line crosses the Y axis Question 16 (0.5 points) When using correlation in inferential statistics, if the variability for variable Y is about the same for each value of variable X, the assumption of _______ has been met. Question 16 options: Homoscedasticity Rho Attenuation Heteroscedasticity Question 17 (0.5 points) A concept that underlies both correlation and regression is: Question 17 options: Predictability Validity Shared variance Within vs. between group variance