Correlation

Question 1

Define bivariate data (giving an example):

Answer 1

Data which has pairs of values for two variables- these variables are often related.
For example, someone may have done 35 breaths per minute and 80 pulse beats per minute at the same time.

Question 2

What are the features of a scatter diagram?

Answer 2

Independent and dependent variable.
Crosses that represent a data point.
Crosses on the graph tend to either form a negative or positive gradient.
A line of best fit can be drawn when diagram shows correlation.

Question 3

What diagram can bivariate data be represented on?

Answer 3

Scatter diagram.

Question 4

What is the regression line on a scatter graph (give another name for it)?

Answer 4

A type of line of best fit also know as least squares regression line.
Minimises the sum of the squares of the distances of each data point from the line (minimises d1²+d2²+…..).

Question 5

What is the formula of a regression line?

Answer 5

y= a + bx