Chapter 11 Factorial ANOVA Types of Independent
Chapter 11 Factorial ANOVA
Types of Independent Variables
Between and Within Factors Fixed and Random Factors Between or Within Fixed or Random • A fixed factor - the researcher has selected the levels of interest • A random factor - the levels have been selected at random from all possibilities • Random factors are relatively rare • Examples include altitude or age
Between and Within Factors Fixed and Random Factors (Cont.) Fixed factor • Results of an experiment apply to the selected levels only.
Random factor • Trends in the data may be applied across the spectrum of all possible levels.
SPSS Steps Place effects in “Fixed” or “Random” windows. All other SPSS commands remain the same No post hoc tests for Random Factors
Summary Many possible combinations of between, within, fixed, and random factors as the number of factors increases. SPSS will determine the correct F-ratios as long as you enter the factors correctly.
Types of Independent Variables
Between and Within Factors Fixed and Random Factors Between or Within Fixed or Random • A fixed factor - the researcher has selected the levels of interest • A random factor - the levels have been selected at random from all possibilities • Random factors are relatively rare • Examples include altitude or age
Between and Within Factors Fixed and Random Factors (Cont.) Fixed factor • Results of an experiment apply to the selected levels only.
Random factor • Trends in the data may be applied across the spectrum of all possible levels.
SPSS Steps Place effects in “Fixed” or “Random” windows. All other SPSS commands remain the same No post hoc tests for Random Factors
Summary Many possible combinations of between, within, fixed, and random factors as the number of factors increases. SPSS will determine the correct F-ratios as long as you enter the factors correctly.
