Statistics 6+

Question 1

What are the similarities of non-linear regression and linear regression?

Answer 1

There is a slope/gradient value and there is a constant value which determines the y-intercept. They also both have independent and dependent variables

Question 2

What are the differences of non-linear regression and linear regression?

Answer 2

Non-linear is characterised by the process of when changes are made to the predictor value (x) they do not result in the same degree of changes to the corresponding y values

Question 3

What is a slight problem of non-linear regression in terms of its variability?

Answer 3

there are so may forms that it can take

Question 4

What is the general format of non-linear regression curves and other non-linear curves?

Answer 4

Y = A + bX

Question 5

What do the A and B values of any regression line mean for non-linear regressions?

Answer 5

B is either a multiplication factor or a power which determines the curvature
A is either a multiplicative or an additive which represents the location of the curve which has been determined by B

Question 6

What is a multiplicative?

Answer 6

means you multiply any x-value by the same number every time to get the corresponding y-value

Question 7

What can a multiplicative also be and how?

Answer 7

A divide function by multiplying by a reciprocal

Question 8

What is an additive?

Answer 8

means you add the same number to any x-value to get the corresponding y-value

Question 9

What can additive also be and how?

Answer 9

subtraction by adding a negative value

Question 10

Which important regression statistics are also used/available to understand the regression line in SPSS?

Answer 10

R square
F ratio
T value

Question 11

What is the general format for a quadratic regression line?

Answer 11

aX^2 + bX + c

Question 12

What do the a, b and c constants all do in a quadratic function?

Answer 12

a determines whether the curve is u or n shaped and the greater the value the greater the intensity of this shape
b determines the location of the parabola vertex along the parabola
c determines the y-intercept

Question 13

What is the general format for a cubic regression line?

Answer 13

ax^3 + bx^2 + cx + d

Question 14

What does the a constant do?

Answer 14

Determines whether the cubic curve goes from down to up then down or the opposite