| A positive correlation | - When variables increase together
- Relationship |
| A negative correlation | - As one variable increases the other decreases
- Relationship |
| No correlation | - The two variables are uncorrelated |
| Strengths of a correlation | - Calculates strength of relationship between variables
- If get strong correlation, good starting point for experiement
- Can be really flexible |
| Weaknesses of correlation | - Cannot identify cause and effect - just patterns
- There may be a false correlation |
| How to measure the strength of a correlation - Use a Correlation test eg Spearman’s Rho | - Gives number called a correlation coefficient
- Number between -1 and +1 and states how strong a correlation is |
| Different coefficients related to correlations | - Number close to +1 = positive correlation
- Number close to -1 = negative correlation
- Number close to 0 = no correlation |
| Scatter diagrams | - Title, labelled axes, appropriate units
- No line of best fit
- Doesn't matter which variable is on the x or y axis
- Shows correlation but no conclusion about hypothesis |
| Usefulness of scatter diagrams | - Shows correlation between co-variables |
