Correlational analysis and graphs

What are correlations

• Non experimental method

investigate STRENGTH and DIRECTION of a relationship between two co-variables

Why use a correlation

Ethical or practical reasons

(When a lab wouldn’t be suitable)

Correlation coefficient

Represents the strength and direction of the relationship

0.8 or above

Advantages of correlations analysis

• Use for topics that are sensitive or unethical

  → no deliberate manipulation of variables required so avoids ethical issues (e.g. harm)

• Relatively quick and inexpensive

Disadvantages of correlational analysis

• Only identify a link

  → can’t establish cause and effect

Ordinal data

• Continuous

• Individual scores

• More sophisticated

Often displayed in line graph, scatter graph, histogram

Nominal level data

• Categorical

• No independent scores

• More basic

Often displayed in a bar chart

Marking points for a graph

• Label axis

• Plot data

• Title

• Scale