AP Statistics Unit 2

scatterplot

a graphical display that shows the relationship between two quantitative variables

explanatory variable

the independent variable that attempts to explain the relationship with the other variable. It becomes the x variable on the graph

response variable

the dependent variable that responses to the other variable being used. It becomes the y variable

correlation

the numerical measure r that measures the strength and direction of the linear relationship

outlier

a point that lies outside the overall pattern of the data

lurking variables

A variable other than x & y that simultaneously affects both variables and accounts for the correlation between the two

residual

the difference between the actual value of y and the predicted value of y for a specific x value

predicted value

the value y, found for a specific x from the regression equation

slope

the change in the predicted response variable for every unit increase in the explanatory variable

least squares regression line

also know as the regression line or line of best fit it is the line that minimizes the sums of the squares of the vertical distances from the actual points to the line

y-intercept

the value of the resonse variable when the explanatory variable is zero

coefficient of determination

the value of r-dquared which tells us what percent of the variability in y can be explained by the linear regression of y on x.

extrapolation

when we attempt to predict values for the reposnse variable that are outside the domain of the explanatory variable

leverage point

a point that has a strong effect on the regression line pulling the regression line toward it

influential point

a point that has a strong effect on the regression line if it is removed