Unit 2 Chapter 6-7 Quiz

R²

R²% of the response variable is accounted for by our linear model

Slope: b or b1

Our model predicts the response variable will (increase/decrease) units, on average, for every extra unit of the explanatory variable

Intercept

Our model predicts “a” units on average of the response variable when we have 0 units of the explanatory variable

how to analyze a residuals plot

is the association random?

does the residuals plot display a fairly even spread?

what does not verify a linear model?

R²

as R² goes up…

the better the LSRL will predict ‘y’ for a given ‘x’

what is a residual?

actual y - predicted y

what do you need to say to describe an association

context, units, direction, strength, form (linear, curved), unusual features, SENTENCE OF ASSOCIATION

purpose of correlation: ‘r’

gives direction (sign) and a measure of strength/more objective measure of strength

properties of ‘r’

r is dimensionless, sign of r gives direction, value of r will always lie -1<r<1, non-resistant, LTs do not affect r (but reexpressions do), not affected by which variable on which axis

Standard deviation

The actual values of the response variable vary from our model’s predicted values (with a standard deviation of ____ units) or (with an average deviations of _____ units)