Key Terms

analysis of variance
also referred to as ANOVA: a method of testing whether the means of three or more populations are equal

 
The method is applicable if
  • all populations of interest are normally distributed,
  • the populations have equal standard deviations, and
  • samples (not necessarily of the same size) are randomly and independently selected from each population.

The test statistic for analysis of variance is the F ratio.

one-way ANOVA
a method of testing whether the means of three or more populations are equal; the method is applicable if
  • all populations of interest are normally distributed,
  • the populations have equal standard deviations,
  • samples (not necessarily of the same size) are randomly and independently selected from each population, and
  • there is one independent variable and one dependent variable.

The test statistic for analysis of variance is the F ratio.

variance
mean of the squared deviations from the mean; the square of the standard deviation

 
For a set of data, a deviation can be represented as xx¯x¯ where x is a value of the data and x¯x¯ is the sample mean. The sample variance is equal to the sum of the squares of the deviations divided by the difference of the sample size and 1.