Chapter 16 Flashcards
What is a Simple Linear Regression and How do we use it?
MASTERING THE CONCEPT Page 423
16.1: Simple linear regression allows us to determine an equation for a straight line that predicts a person’s score on a dependent variable from his or her score on the independent variable.
We can only use it when the data are approximately linearly related.
What is the formula for predicting a z score by the Pearson Correlation Coefficient?
MASTERING THE FORMULA Page 424
16-1: The standardized regression equation predicts the z score of a dependent variable, Y, from the z score of an independent variable, X. We simply multiply the independent variable’s z score by the Pearson correlation coefficient to get the predicted z score on the dependent variable:
z Yˆ = (rXY)(zX)
What is regression to the mean
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■■Regression to the mean is the tendency of scores that are particularly high or low to drift toward the mean over time.
What is the intercept in a regression?
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■■The intercept is the predicted value for Y when X is equal to 0, which is the point at which the line crosses, or intercepts, the y-axis.
Explain the slope of a regression?
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■■The slope is the amount that Y is predicted to increase for an increase of 1 in X.
What is the simple regression formula?
MASTERING THE FORMULA Page 426
16-2: The simple linear regression equation uses the formula:
Ý= a + b(X).
In this formula, X is the raw score on the independent variable and Ý is the predicted raw score on the dependent variable. a is the intercept of the line, and b is its slope.
What is the formula for standardized regression coefficient ß?
MASTERING THE FORMULA Page 430 16-3:
The standardized regression coefficient, ß, is calculated by multiplying the slope of the regression equation by the quotient of the square root of the sum of squares for the independent variable by the square root of the sum of squares for the dependent variable:
ß = (b)*(√SSX / √SSY)
What is ß or Beta Weight?
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■■The standardized regression coefficient, a standardized version of the slope in a regression equation, is the predicted change in the dependent variable in terms of standard deviations for an increase of 1 standard deviation in the independent variable; symbolized by ß and often called beta weight.
Explain Standardized Regression Coefficient?
MASTERING THE CONCEPT Page 431
16.2: A standardized regression coefficient is the standardized version of a slope, much like a z statistic is a standardized version of a raw score.
For simple linear regression, the standardized regression coefficient is identical to the correlation coefficient.
This means that when we conduct hypothesis testing and conclude that a correlation coefficient is statistically significantly different from 0, we can draw the same conclusion about the standardized regression coefficient.
How does regression work with correlation?
>Regression builds on correlation, enabling us not only to quantify the relation between two variables but also to predict a score on a dependent variable from a score on an independent variable. Page 431
How does Standardized Regression Work?
>With the standardized regression equation, we simply multiply a person’s z score on an independent variable by the Pearson correlation coefficient to predict that person’s z score on a dependent variable. Page 431
Explain Raw-Score Regression?
>The raw-score regression equation is easier to use in that the equation itself does the transformations from raw score to z score and back. Page 431
What is the standardized regression equation used for?
>We use the standardized regression equation to build the regression equation that can predict a raw score on a dependent variable from a raw score on an independent variable. Page 431
How do we graph the regression line?
>We can graph the regression line,
Ý= a + b(X)
based on values for the y intercept, a; the predicted value on Y when X is 0; and the slope, b, which is the change in Y expected for a 1-unit increase in X.
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What is does the standardized regression coefficient tell us?
>The slope, which captures the nature of the relation between the variables, can be standardized by calculating the standardized regression coefficient.
The standardized regression coefficient tells us the predicted change in the dependent variable in terms of standard deviations for every increase of 1 standard deviation in the independent variable.
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