The analysis of variance—abbreviated as ANOVA —is used when the means of three or more samples need to be tested for equality. For example, ANOVA can help a consumer select a car after comparing the average fuel consumption of cars from different companies. The samples used for the ANOVA test should have three essential characteristics or statistical assumptions. The first assumption is that samples should be drawn from normally distributed populations. The second assumption is that samples should be selected randomly and independently from the populations. The third assumption is that populations of samples should have equal variances. There are two commonly used types of ANOVA tests: one-way ANOVA and two-way ANOVA. One-way ANOVA is used when samples are defined or categorized by one factor or treatment, and two-way ANOVA is used when samples are defined or categorized by two factors or treatments. ANOVA has a wide application in life science, forensics, social sciences, and business administration.