6.2 Research Methods (Correlations + Data)

Question 1

What is a correlation?

Answer 1

When a researcher investigates an association between two variables

Question 2

What are co-variables?

Answer 2

The variables investigated within a correlation

Question 3

What are the 3 types of correlation?

Answer 3

- Positive correlation: as one co-variable increases, so does the other
- Negative correlation: as one co-variable increases, the other decreases
- Zero correlation: when there is no relationship between the co-variables

Question 4

What is the difference between correlations and experiments?

Answer 4

In an experiment, the researcher manipulates the IV to measure the DV, whereas in a correlation there is no manipulation therefore it is difficult to establish cause-effect

Question 5

Strengths and limitations of correlations

Answer 5

• Can lead to further research (if variables strongly related, typically a starting point before committing to experimental study)
• Less time-consuming (can use secondary data)
• Does not demonstrate cause/effect
• Third variable problem (influence of another untested variable)

Question 6

What are the 4 types of data?

Answer 6

- Quantitative data: expressed numerically
- Qualitative data: expressed in words rather than numbers/statistics
- Primary data: original data collected by the researcher specifically for the purpose of the investigation
- Secondary data: collected by someone other than the researcher

Question 7

AO3 for qualitative and quantitative data

Answer 7

• Qualitative has more richness of details
• Qualitative has more external validity (meaningful insight)
• Qualitative more difficult to analyse
• Qualitative more subject to bias/preconceptions

Question 8

AO3 for primary and secondary data

Answer 8

• Primary can specifically target the information required
• Collecting primary data is time-consuming
• Secondary data leads to invalid conclusions (may be outdated/incomplete)

Question 9

What are the 3 measures of central tendency?

Answer 9

• Mean (adding up all the values and dividing by the number of values)
• Median (the central value when arranged from lowest to highest)
• Mode (the most frequently occurring value)

Question 10

What are the 2 measures of dispersion?

Answer 10

• Range (when the lowest score is subtracted from the highest score)
• Standard deviation (how far scores deviate from the mean)

Question 11

What is a measure of dispersion?

Answer 11

A measure of the spread or variation in a set of scores

Question 12

What is a measure of central tendency?

Answer 12

A measure of the average value in a set of data

Question 13

What is a disadvantage of the mean compared to the median in relation to representation?

Answer 13

The mean is easily distorted by extreme values, meaning that it is unrepresentative of the overall data

Question 14

What is a disadvantage of using median?

Answer 14

Lower and higher numbers are ignored, but extreme values may be important

Question 15

What does a low and high standard deviation suggest?

Answer 15

• Low = data clustered around the mean, all participants responded in a similar way
• High = greater spread/dispersion of data, not all participants were affected by the IV in the same way

Question 16

What is an advantage and disadvantage of the range?

Answer 16

• Easy to calculate
• Only accounts for two most extreme values (unrepresentative of data set)

Question 17

Why may standard deviation be better than range?

Answer 17

More precise as it includes all values in final calculation (however can be distorted by single value)

Question 18

What are the 3 types of tables/graphs?

Answer 18

• Scattergram
• Bar chart
• Histogram

Question 19

What is a normal distribution?

Answer 19

A symmetrical spread of frequency data that forms a bell-shaped pattern (the mean, median, mode located at the highest peak)

Question 20

What is a skewed distribution?

Answer 20

A spread of frequency data that is not symmetrical, data clusters to one end

Question 21

What is a positive skew and what does it suggest?

Answer 21

• A frequency distribution where the long tail is on the positive (right) side of the peak, and most distribution is concentrated on the left
• Mean is dragged towards the tail as it is affected by extreme scores (e.g scores on a difficult test)

Question 22

What is a negative skew and what does it suggest?

Answer 22

• A frequency distribution where the long tail is on the negative (left) side of the peak, and most distribution is concentrated on the right
• Mean is dragged towards the left due to lower scorers e.g on an easy test

Question 23

What is statistical testing?

Answer 23

A way of determining whether hypotheses should be accepted or rejected

Question 24

What is the sign test?

Answer 24

A statistical test used to analyse the difference in scores between related items

Question 25

What are the 3 conditions needed for the sign test?

Answer 25

- Looking for a difference rather than an association - Related design (repeated measures, matched pairs) - Nominal data (organised into categories)

Question 26

How is the calculated value used to determine whether results are significant or not?

Answer 26

The calculated value is compared with the critical value

Question 27

What is a correlation coefficient?

Answer 27

A number between -1 and +1 which represents the direction and strength of a relationship between co-variables

Question 28

What does the value of the correlation coefficient mean?

Answer 28

- The closer the coefficient to -1 or +1, the stronger the relationship between the co-variables - The closer to 0 the weaker the relationship