Interpreting correlations What are Scatter Graphs Scatter graphs

Interpreting correlations….

What are Scatter Graphs? • Scatter graphs are an important type of graph used in geography to find or show a relationship between two sets of data or variables • They can be analyzed to show the extent to which two variables are correlated. • Eg: Is there a relationship between adult literacy levels and GDP?

What do you think we call this type of trend?

• Three possible outcomes exist when the data are plotted: 1. There may be a positive correlation: when higher magnitudes of one thing occur along with higher magnitudes of the other 2. There may be a negative, or inverse correlation when higher magnitudes of one thing lead to lower magnitudes of another 3. There may be not relationship at all

How could correlations be described in even more detail?

If we find a strong correlation does it mean the variables are influencing each other? • Many development indicators are not isolated, but interrelated parts of larger complexes of variables • We may therefore find a negative correlation between literacy and infant mortality, but find that they are in reality both jointly influenced by the level of economic development and are not actually influencing each other much at all • We can determine this by looking at the correlation of the variables in only the low-income countries, for example. We may find little or no correlation once we “control” or hold constant economic development.

Evidence of a correlation does not imply causation: (note the intentionally misleading X axis scale) Source: Church of the Flying Spaghetti Monster. http: //www. venganza. org/about/open-letter/