4.2 the least-squares regression line

Question 1

least-squares regression line

Answer 1

the line that fits the scatterplots best which is caused by their sum of sqaured vertical distances is at its smallest as possible.

Question 2

what is the least-squares regression line used for?

Answer 2

to predict a variable aka the outcome variable, or response variable (usually the y-variable)

Question 3

explanatory variable or predictor variable

Answer 3

the variable given (usually the x-variable)

Question 4

how to get the LSR lines on the ti-84

Answer 4

1) enter the x-values in L1 and y-values in L2. 2) press Stat and the right arrow key to see the Calc menu. 3) pick the LinReg(a+bx) or (option 8) and enter to find a and b. The equal should be written as y with a karat on top=a+b times x. (no parentheses).

Question 5

finding the outcome variable using the equation

Answer 5

sub in a value for the explanatory variable for x.

Question 6

y-hat

Answer 6

LOL. this is what the y with a karat on top is called ig. it means approximate value

Question 7

b-naught

Answer 7

the b symbol with a 0 subscript. this si the point where the line crosses the y-axis. this is useful only if the data has both positive an dneg x-values, then the y-intercept is the estimated outcome when the value of the explanatory variable is 0

Question 8

b1 (b-one)

Answer 8

this is the slope. if the values of the explanatory variable for two individuals differ by 1, their predicted values will differ by b1. if the values of the explanatory variable differ by an amount d, their predicted values will differ by b1 times d.

Question 9

no outlier is appropriate to use in the equation aka extrapolation

Answer 9

anything above or below the min and max

Question 10

if there seems to be a pattern with the scatetrplot

Answer 10

not appropriate

Question 11

if the plots are well scattered

Answer 11

appropriate