Flashcards in Multivariable: Linear Regression Deck (19)

Loading flashcards...

1

## What is a regression line

###
a straight line that

describes how a response variable y changes

as an explanatory variable x changes.

2

## what is the formula for a straight line

###
A straight line relating y to x has an equation of the form:

– y = a + bx

• In this equation, b is the slope

– the amount by which y

changes when x increases by

one unit. The number a is the

intercept, the value of y when x

= 0.

--y = b0 + b1x

3

## What is a or b0

### a or b0 is a constant

4

## What is b or b1

### b or b1 is the slope of the line

5

## What is the least-squares regression

###
the technique we use to find the line that

best fits the observations.

6

## What is the The Sum of Squares Regression (SSR) and how do you calculate it

###
The Sum of Squares Regression (SSR) is the sum of the squared differences between the prediction for each observation and the population mean.

SSR + SSE. ((measure of explained variation)+(measure of unexplained variation)

7

##
in multivariable models we have to use the

adjusted R2 bc...

###
...it includes an adjustment for the

increased number of independent variables.

8

## What is the multivariable equation

### y = b0 +b1x1 + b2 x2 + b3x3 +...+ bn xn

9

## How do we predict values of Y

###
we enter in a vector of covariates

and solve

10

## bo is the value of y when...

### x’s = 0 which usually has little meaning

11

## b1...bn are....

###
interpreted as the amount by which y

changes for each 1 unit change in x HOLDING ALL

OTHER VARIABLES CONSTANT

12

## For ANOVA f test what is the simple linear regression equation

### H0: β1= 0 Ha: β1≠ 0

13

## For ANOVA f test what is the multivariate equation

### H0: β1,β2,β3,β4= 0 Ha: β1 or β2 or β3 or β4≠ 0

14

## In multivariable models if the p-value ≤ 0.05 then we...

### – reject the null hypothesis and conclude that at least one parameter estimate has a significant linear relationship with our outcome

15

## In multivariable models if the p-value > 0.05 then we...

### fail to reject the null hypothesis and conclude that none of our parameter estimates has a significant linear relationship with our outcome

16

## What is the adjusted r2 value

###
– the percent of the variation in the outcome that is

explained by the model

17

## What is an F test

###
the global test of significance of the model; are any of the

independent variables related to the outcome?

18

## yi-y

### What is the total variation in the response y is expressed by the deviations

19