A study of the properties of metal plate-connected trusses used for roof support ("Modeling Joints Made with Light- a.Ho Gauge Metal Connector Plates," Forest Products J., 1979: 39-44) yielded the following observations on axial-stiffness b. Ha index (kips/in.) for plate lengths 4, 6, 8, 10, and 12 in: Does variation in plate length have any effect on true aver- c. Decision? (Reject or Do not Reject) age axial stiffness? State and test the relevant hypotheses Let alpha=.01 d. Minimum difference to be significant (1 decimal) Differences (1 decimal) 346. 317.1 370.4 361.3 277 330.4 235.3 368.8 4_6 379. 359.7 350.6 402.7 379.6 338.2 373.2 368.1 4 8 369.7 350.6 405.1 374.3 390.1 380.4 385.7 440 4_10 444.2 390.2 10 371.4 443.3 396.3 384.8 383.8 471.3 4_12 438 432.9 455.3 380 435.7 406.8 423.5 12 492.6 6_8 6_10 Determine if there are significant differences in the means of the plates. Use Tukey's procedure to determine which plates differ significantly 6 12 8_10 8_12 10_12