A study of the properties of metal plate-connected trusses used for roof support (“Model...

A study of the properties of metal plate-connected trusses used for roof support (“Modeling Joints Made with Light- Gauge Metal Connector Plates,” Forest Products J., 1979: 39–44) yielded the following observations on axial-stiffness index (kips/in.) for plate lengths 4, 6, 8, 10, and 12 in:

Does variation in plate length have any effect on true average axial stiffness? State and test the relevant hypotheses using analysis of variance with α = .01. Display your results in an ANOVA table.