Correlation

Question 1

What is correlation

Answer 1

a statistical technique that is used to measure
and describe the relationship between two variables that are
simply observed as they exist naturally in the
environment—there is no attempt to control or manipulate
the variables.

Question 2

Correlation analysis

Answer 2

studies the closeness of the relationship
between two or more variables

• It is often used to describe the linear relationship between two
  continuous variables

Question 3

Positive correlation

Answer 3

means that as one variable increases,
the other does too.

Question 4

Negative correlation

Answer 4

means that when one variable
increases, the other one decreases.

Question 5

The calculation of correlation between two variables is a

Answer 5

descriptive measure

Question 6

Inferential procedure

Answer 6

testing the correlation for
significance. It tells us the probability of finding that level
of ‘togetherness’ between our samples if there is no actual togetherness in the
population.

Question 7

Strength of correlation

Answer 7

the degree to which one
variable does tend to vary with the other.

Question 8

The size of the covariance is influenced by

Answer 8

the scale of the data elements, and so in
order to eliminate the scale factor, the correlation coefficient is used as a scale-free
metric of the linear relationship.

Question 9

Correlation coefficient

Answer 9

The figure arrived at to express the relationshipGood

Question 10

Goodness of fit

Answer 10

quality of parameter estimation (sometime called model optimization) depends
on

Question 11

Parameters

Answer 11

help to define the properties and behaviour of the model.

Question 12

Least square method

Answer 12

finds best fit values of the parameters that make the model do as
good a job as possible at predicting Y (dependent variable) from X (independent
variable).

Question 13

Error

Answer 13

the difference between actual and predicted value of the outcome of the
model.