* Introduction to statistical modelling 2: categorical variables and interactions in linear regression.
- In the first article in this series we explored the use of linear regression to predict an outcome variable from a number of predictive factors. It assumed that the predictive factors were measured on an interval scale. However, this article shows how categorical variables can also be included in a linear regression model, enabling predictions to be made separately for different groups and allowing for testing the hypothesis that the outcome differs between groups. The use of interaction terms to measure whether the effect of a particular predictor variable differs between groups is also explained. An alternative approach to testing the difference between groups of the effect of a given predictor, which consists of measuring the effect in each group separately and seeing whether the statistical significance differs between the groups, is shown to be misleading.
Overview of noun factor
The noun factor has 7 senses (first 4 from tagged texts)
1. (31) factor -- (anything that contributes causally to a result; "a number of factors determined
the outcome")
2. (8) component, constituent, element, factor, ingredient -- (an abstract part of something;
"jealousy was a component of his character"; "two constituents of a musical composition are melody
and harmony"; "the grammatical elements of a sentence"; "a key factor in her success"; "humor: an
effective ingredient of a speech")
3. (4) divisor, factor -- (one of two or more integers that can be exactly divided into another
integer; "what are the 4 factors of 6?")
4. (1) agent, factor, broker -- (a businessman who buys or sells for another in exchange for a
commission)
5. factor -- (any of the numbers (or symbols) that form a product when multiplied together)
6. factor -- (an independent variable in statistics)
7. gene, cistron, factor -- ((genetics) a segment of DNA that is involved in producing a polypeptide
chain; it can include regions preceding and following the coding DNA as well as introns between the
exons; it is considered a unit of heredity; "genes were formerly called factors")
Overview of verb factor
The verb factor has 3 senses (first 1 from tagged texts)
1. (2) factor, factor in, factor out -- (resolve into factors; "a quantum computer can factor the
number 15")
2. factor -- (be a contributing factor; "make things factor into a company's profitability")
3. factor, factor in, factor out -- (consider as relevant when making a decision; "You must factor
in the recent developments")
--- WordNet end ---