What is linearity?
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What is linearity?
- Linearity is a straight-line relationship between variables.
Why is linearity important?
- Correlation and regression tests rests upon the assumption of linearity because they only capture linear relationships. Not all relationships are linear. Just as not all variables are normally distributed in the real-world, not all relationships are supposed to be linear.
- There could be a non-linear relationship for USA immigrants between length of residence in USA and depression. It is a U-shaped relationship. Depression levels starts high during the first few years of initial resettlement, then decreases for a while as they adjust to the new environment, and then increases again later in life. - Another example of a non-linear relationship is mortality and water consumption. Absence of water increases mortality, middle levels of water decreases mortality, but too much water increases mortality.
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