Statistics L1

Question 1

What do we use to estimate linear regression?

Answer 1

Equation of a straight line

y = mx + c

Question 2

What is the least-squares criterion?

Answer 2

Ensure equal total distance of the points either side of a regression line, to the line. The value for this distance should aim to be as small as possible

Question 3

What two things are needed to determine the visual unexplained and explained variance?

Answer 3

Regression line and mean value of y line

Question 4

How do you determine the explained and unexplained variance visually?

Answer 4

Explained = the distance between the regression line (predicted values) and the mean value of y line
Unexplained = the distance between the observed y value and the mean y-value line

Question 5

What is the f-ratio?

Answer 5

The ratio of explained to unexplained variance

Question 6

What is the ideal condition for an f-ratio

Answer 6

f > 1

Question 7

What is the coefficient of explanation and what is its notation?

Answer 7

r^2 = the proportion/percentage of variance that is explained by the model

Question 8

What distinguishes linear and multiple regression?

Answer 8

linear only involves only 2 variables whereas multiple regression involves many variables

Question 9

What is factor analysis?

Answer 9

Technique to determine whether a group of results can be attributed to a singular or multiple underlying factors and to what extent. Transform variables in to factors

Question 10

What is cluster analysis?

Answer 10

Technique to determine whether a group of results can be clumped/clustered together to reflect meaningful and definable piles of similar information e.g. whether they all coordinate based on colour