Chapter 4: Correlation

Question 1

What is bivariate data?

Answer 1

Bivariate data is data which has pairs of values for two variables.

Question 2

What is a least squares regression line?

Answer 2

A least squares regression line is a straight line that minimises the sum of the squares of the distances of each data point from the line.

Question 3

What does the coefficient b show in a regression line with equation y = a + bx?

Answer 3

The coefficient b tells you the change in y for each unit change in x.

• If the data is positively correlated, b will be positive.
• If the data is negatively correlated, b will be negative.

Question 4

What are the limitations of predictions using the regression line from a set of bivariate data.

Answer 4

• It can only be used to make a prediction for the value of the dependent variable from the independent variable.
• You should only interpolate the data.