4. Correlation

Question 1

What are the differen ttypes of correlation ?

Answer 1

Strong Positive correlation
Weak Positive correlation
Zero (no) correlation
Strong negative correlation
Weak Negative correlation

Question 2

what does the gradient mean in the linear regression equation.

when …. increases by 1 the ….. will increase/decrease by x

Answer 2

example 1
t = 6.3 + 2.64n
when n increases by 1 then time increaes by 2.64 mins

Eample 2
g = 99.6 - 5.2 t

when temperature increases by 1 degree
n decreases by 5.2

Question 3

What is the regression line ?
when is it a valid model

Answer 3

A regression line is a valid model when the data shows a linear correlation, the stronger the correlation, the more accurate the regression line will model the data

Question 4

What is Interpolation?

Answer 4

Using regression line to make prediction for values of the dependent variable that are withing the range of the given data.

Question 5

What is Extrapolation?

Answer 5

Making a predictions based on a value outside the range of given data , provides a less reliable estimate.

Question 6

What is bivariate data?

Answer 6

Bivariate data has pairs of values for two variables, represented on a scatter diagram.

Question 7

What is a casual relationship?

Answer 7

Two variables have a casual relationship if a change in one variable causes a change in the other.