Lesson 4: Correlations

Question 1

correlation coefficient

Answer 1

the strength of a correlation

Question 2

advantages of using correlations

Answer 2

• allows psychologists to establish the strength of the relationship between two variables more precisely
• predictions can be made about one variable based on what is known about another variable once a correlation has been established
• allows researchers to investigate things that could not be manipulated experimentally for ethical or practical reasons

Question 3

disadvantages of correlations

Answer 3

• correlational analysis cannot demonstrate cause and effect
• a correlation being present does not automatically mean there is a relationship between the two variables, there may be a third unknown variable which influences both
• can only measure linear relationships and does not detect curvilinear relationships; when there is a positive relationship up to a point, but after that the relationship becomes negative (or vice versa)

Question 4

differences between correlations and experiments

Answer 4

• an experiment isolates and manipulates the independent variable to observe its effects on the dependent variable, and controls the environment in order to eliminate extraneous variables
• experiments establish cause and effect
• a correlation looks for a relationship between two co-variables
• an experiment can predict cause and effect (causation) but a correlation can only predict a relationship, as a third, unknown extraneous variable may be involved