L4 - Correlarions

Question 1

Correlation

Answer 1

It’s a technique for analysing the strength of the relationship between two quantitative variables known as co-variables

Question 2

Positive correlation

Answer 2

This means that as one variable increases the other variable increases

E.g. as temp increases so does ice cream’s sold

Question 3

Negative correlation

Answer 3

Means that as one variable increases the other decreases
E.g. more video games played, lower the grades

Question 4

No correlation

Answer 4

No relationship between the two variables
E.g. head size and IQ levels

Question 5

Correlation coefficient

Answer 5

The strength of the correlation
Between -1 and +1
0 is no correlation
-1 is a strong negative correlation
+1 is a strong positive correlation
Closer to -1/+1 the stronger it is

Question 6

What are correlations plotted on

Answer 6

Scattergraph/Scattergram

Question 7

Advantages

Answer 7

• establish strength
• investigate variables that can’t be manipulated
• predications can be made

Question 8

Disadvantages

Answer 8

• cause & effect
• 3rd variable
• linear relationships only

Question 9

Establishes strength

Answer 9

Correlations allows psychologists to establish the strength of the relationship between two variables and measure it precisely for example there might be a very strong positive relationship +1 between the variables of being very wealthy and being very happy

Question 10

Investigate variables that can’t be manipulated

Answer 10

Correlations allows researchers to investigate things that could not be manipulated experimentally for ethical or practical reasons, for instance a natural relationship might occur between the variables of being highly stressed and having cardiovascular disease. It would be unethical to intentionally inflict stress or cardiovascular disease upon participants, but if it occurred naturally then it would be fine to study this issue

Question 11

Predictions can be made

Answer 11

Once a correlation has been conducted predictions can be made about one of the variables based on what is known about the other variable. For instance if we know that high stress causes high cholesterol, then we might state that as stress increases, cholesterol might increase. This can help inform conclude that lowering stress might lower cholesterol.

Question 12

Cause and effect

Answer 12

Correlational analysis cannot demonstrate cause and effect; we cannot tell which variable influences the other. For instance can we sure that high stress causes an increase in cholesterol, or does having high cholesterol cause an increase in stress?

Question 13

3rd variable

Answer 13

Even if there is a correlation between two variables it may be the case that the variables are not actually related but that there is a third unknown variable which influences both. For instance maybe an unhealthy diet might cause an increase in cholesterol (rather than stress causing the increase?

Question 14

Only measures linear relationships

Answer 14

Correlations can only measure linear relationships and does not detect curvilinear relationships. This is when there is a positive relationship up to a certain point but after that the relationship becomes negative or (vice versa)