Week 7 (regression Analysis)

Question 1

What is regression analysis?

Answer 1

Regression analysis describes the dependence of one variable on one or more variables

Question 2

How does RA work?

Answer 2

It uses the independent variable to estimate the dependent variable

Question 3

2 assumptions for bivariate regression analysis?

Answer 3

• relationship between variables is linear

- both variables must be interval or ratio scale

Question 4

2 equations of line for BRA and meaning of each letter?

Answer 4

y = a + bx + e

y = dependent variable
x = independent variable
b = slope
e = error term
a = intercept

y^ = a + bx

y hat is line of best fit

Question 5

What does the LofBF do?

Answer 5

It minimises the sum of squared values between the actual and predicted y values

Question 6

What is error?

Answer 6

The vertical difference between an observation and the regression line

Question 7

How to find intercept (a)?

Answer 7

a = ybar - bxbar

Question 8

Equation for slope?

Answer 8

b = r(Sy/Sx)

Sy = sample s.d. of y
Sx = sample s.d. of x

Question 9

What is the purpose of a dummy variable?

Answer 9

A variable used to include qualitative and nominal data in a regression