Correlations

Question 1

What is a correlation

Answer 1

• Determining the extent of an association between two co-variables

Question 2

What are the 2 variables called that we compare in a correlation

Answer 2

Co-variables

Question 3

What are the words that we CANNOT use when talking about correlations

Answer 3

• linked
• difference
• cause
• effect
• association
• DV / IV

Question 4

What are the 3 types of correlation

Answer 4

• positive correlation
• negative correlation
• no correlation

Question 5

What is a positive correlation

Answer 5

• As one variable increases, the other also increases
• likewise for if one decreases
  —> results on a graph should resssemble a tick

Question 6

What is a negative correlation

Answer 6

• as one variable increases, the other decreases

Question 7

What is no correlation

Answer 7

• The variables aren’t linked
• there is no visible pattern in data

Question 8

How do you write a Null hypothesis about a correlation

Answer 8

There will be no significant relationship/correlation between ______ and ______

Question 9

How do you write a directional alternative hypothesis about a correlation

Answer 9

There will be a significant positive/negative relationship/correlation between ______ and ______

Question 10

How do you write a non-directional alternative hypothesis about a correlation

Answer 10

There will be a significant relationship/correlation between ______ and ______

Question 11

What type of diagram is a correlation always displayed on

Answer 11

Scatter diagram

Question 12

You get 4 marks in an exam for drawing a scatter diagram. What are those 4 marks for?

Answer 12

• Title: ‘A scatter diagram to show the relationship between ______ and ______’
• results being plotted correctly
• title (including units) on both x and y axis (e.g. reaction time (seconds))
• an appropriate scale bar

Question 13

When asked ‘Outline 2 findings from the scatter diagram (2)’ what are the 2 possible findings that you can comment on

Answer 13

• type of relationship (Positive/negative/no relationship)
• strength of relationship (strong/weak/perfect)
• identifying outliers — results that deviates from the trend (NOTE: you get no marks for calling it an anomaly)

Question 14

Draw what the different scatter diagrams look like (Perfect negative correlation —> perfect positive correlation)

Answer 14

Question 15

What are the strengths of correlations

Answer 15

• Correlations allow researchers to investigate naturally occurring variables that may be unethical or impractical to test experimentally
• allows researchers to clearly see if there is a relationship between variables
• allows researchers to work out if further investigations is necessary, so could be used as a pilot study to avoid a costly experiment. If there is only a weak relationship found then perhaps an experiment isn’t worth it
• Easy to replicate (assuming the data collection methods are standardised)

Question 16

What is the weakness to correlations

Answer 16

• correlation cannot be taken to mean causation even if there is a strong association between 2 variables we can’t say one causes the other. There may be other intervening variables that explains the link between the co-variables
• people jump to causal conclusions and research can be misinterpreted so improvement programmes or treatments or policy changes may be incorrectly implemented
• the methods used to collect the data may lack internal/external validity

Question 17

When asked an exam Q on outlining 1 weakness of a correlation method in a particular study, how should you answer it?

Answer 17

PEE
- Point: e.g. correlation doesn’t = causation because they weren’t manipulated and there could be intervening variables
- Example: make it relevant to the Q. E.g. there are many intervening variables between ______ and ______, such as ______
- Elaborate: This is a weakness because…..

Question 18

What is a spearman’s Rho

Answer 18

• an inferential statistical test
• it is the only test that can analyse if there is a relationship (note: all other tests find a difference, not relationship)
• it is used for a researcher to state whether the findings are significant or not
• produces an observed value that falls between -1 and +1

Question 19

What is an observed value

Answer 19

• sometimes referred to as the ‘correlation coefficient’ or ‘r’ or ‘rho’
• it comes from a Spearman’s Rho statistical test calculation
• it falls between -1 and +1

Question 20

What is a critical value

Answer 20

• the value the observed value is compared to
• it is produced by a critical value table
• to be significant, the observed values has to be greater than or = to the critical value.
  —> NOTE: it’s not always given to you in an exam. Although you don’t have to calculate it, you will have to find it

Question 21

If the relation ship is significant, which hypothesis do we accept/reject

Answer 21

• accept an alternative
• reject a null

Question 22

“A psychologist found that, after analysing the data with a Spearman’s Rho test, the observed value was 0.56. The critical value is 0.40.”

State whether the psychologist should accept or reject the null hypothesis + why

Answer 22

• The psychologist should reject the null hypothesis
• because the observed value of 0.56 is GREATER THAN the critical value of 0.40 the results ARE SIGNIFICANT
  —> NOTE: if you copy these wordings, you will get full marks

Question 23

“A psychologist found that, after analysing the data with a Spearman’s Rho test, the observed value was -0.78. The critical value is 0.31.”

State whether the psychologist should accept or reject the null hypothesis + why

Answer 23

• The psychologist should reject the null hypothesis
• because the observed value of -0.78 is GREATER THAN the critical value of 0.31 the results ARE SIGNIFICANT
  —> NOTE: just ignore the “-“ sign.