Lesson 3 - Correlations

Question 1

What are correlations?

Answer 1

Correlations illustrate the strength and direction of a relationship between two variables.

Question 2

What kind of graph are correlations plotted on?

Answer 2

Scatter graph.

One variable is plotted on the y-axis and the other on the x-axis.

Question 3

What is a positive correlation?

Answer 3

When both variables increase or decrease.

Eg, the higher the temperature, the higher the ice cream sales.

Question 4

What is a negative correlation?

Answer 4

When one variable increases, the other decreases.

Eg. the more you revise, the less likely you are to fail.

Question 5

What is a no correlation?

Answer 5

Where there is no significant relationship between the two variables

Question 6

What is a correlation coefficient?

Answer 6

A number between +1 and -1 which is calculated by a Spearman’s Rho or Pearson’s R test.
The closer to +1 the number is, the more positive the correlation is. The closer to -1 the number is, the more negative the correlation is.
The number will be the deciding factor in whether to accept or reject the correlational hypothesis.

Question 7

What is the difference between a correlation and an experiment?

Answer 7

• The IV is manipulated in an experiment, meaning cause and effect can be determined. However, in a correlation, the variables are simply measured, so cause and effect cannot be determined.
• There may be intervening variables in a correlation which can be controlled or eliminated in an experiment.

Question 8

Strengths of correlations?

Answer 8

• Useful for preliminary research no future research.
• Quick and cheap to carry out
• No ethical issues

Question 9

Weaknesses of correlations?

Answer 9

• Only shows relationship, not cause and effect
• Could be a third variable that caused the relationship between the two variables
• Correlational data can be misused in media.