ANOVA, or analysis of variance, is the appropriate statistical technique when comparing the means of three or more groups. In this case, the plant manager wants to compare production output for three assembly lines, so ANOVA is the correct method because it can test whether the differences among the group means are statistically significant. It does not directly identify the reason for those differences, nor does it by itself determine the exact production rate mechanism. It also does not simply declare which assembly line has the most output without considering statistical variation. The strength of ANOVA is that it evaluates whether observed differences are likely due to actual process differences rather than random variation. If the ANOVA result is significant, further post hoc analysis may be used to determine which specific lines differ from one another. Therefore, the correct answer is that ANOVA can determine whether there is a significant difference in output among the assembly lines.