=+32. Auto batteries. Most auto batteries are made by just three manufacturers. Each make batteries sold under several brand names. To determine if the average length of life was affected by who made the batteries, samples of batteries of the same specifications were selected for each manufacturer and their length of life in months were recorded. An ANOVA was performed. The partially completed Analysis of Variance is shown here.

ANOVA Source of Variation SS df MS F P-value Manufacturer 2218.228 2 Error 6640.764 132 Total 8858.993 134