AP Stats ch 7 Flashcards

14971239352	model	an equation or formula that simplifies and represents reality	0
14971244239	linear model	is an equation of a line. To interpret a linear model, we need to know the variables (along with their W's) and their units.	1
14971266279	predicted variable	the value of y found for a given x-value in the data. A predicted value is found by substituting the x value in the regression equation. The predicted values are the values on the fitted line; the points (x,y) all lie exactly on the fitted line.	2
14971346286	Residuals	are the differences between data values and the corresponding values predicted by the regression model ----or more generally values predicted by any model.	3
14971389014	Leasts squares	The leasts squares criterion specifies the unique line that minimizes the variance of the residuals or equivalently, the sum of the squared residuals.	4
14971420936	regression to the mean	Because the correlation is always less than 1.0 in magnitude, each predicted y-hat tends to be fewer standard deviations from its mean than its corresponding x was from its mean.	5
14971443263	regression line	The particular linear equation that satisfies the least squares criterion, often called the line of best fit.	6
14971448414	line of best fit		7
14971474381	slope	the slope b1 gives a value in "y-units per x-units." Changes of one unit in x are associated with changed of b1, units in predicted values of y. The slope can be found by	8
14971519393	intercept	b0 gives a starting value in y-units. Its the y value when x is 0	9
14971543837	Se	standard deviation of residuals	10
14971560940	R2	The square of the correlation between x and y gives the fraction of the variability of y accounted for by the least squares linear regressions on x.	11
14971596756	Does the Plot thicken? Condition	The scatterplot or residuals plot should consistent (vertical) spread in y-values.	12