Page 91 - Quantitative Data Analysis

Quantitative Data Analysis
Simply Explained Using SPSS

the analysis of variance an IV is called a factor, the treatment
conditions or groups in an experiment are called the levels of the
factor.
Logic behind ANOVA

ANOVA’s use an F-ratio as its significance statistic which is variance
because it is impossible to calculate the sample means difference
with more than two samples.

Why do we analyze data by using ANOVA instead of
using a bunch of group t test?

 Could be a lot of tests: depending on how many
groups you are comparing. Total number of possible
pairs can be calculated by following formula:

×

o

For example, if there are four groups, there will be six possible pairs:

×

o 1 vs 2, 1 vs 3, 1 vs 4, 2 vs 3, 2 vs 4, 3 vs 4.

 Inflates Type I error rate

The Theory and Applications of Statistical Inferences 75