15.20 The accompanying data resulted from a flammability study in which specimens of five different fabrics were tested to determine burn times.

1 17.8 16.2 15.9 15.5 2 13.2 10.4 11.3 Fabric 3 11.8 11.0 9.2 10.0 4 16.5 15.3 14.1 15.0 13.9 5 13.9 10.8 12.8 11.7 MSTr 5 23.67 MSE 5 1.39 F 5 17.08 P-value 5 .000 The accompanying output gives the T-K intervals as calculated by Minitab. Identify significant differences and give the underscoring pattern.

Individual error rate = 0.00750 Critical value = 4.37 Intervals for (column level mean) - (row level mean)

1 2 3 4 1.938 2 7.495 3.278 -1.645 3 8.422 3.912

-1.050 -5.983 -6.900 4 3.830 -0.670 -2.020 1.478 -3.445 -4.372 0.220 5 6.622 2.112 0.772 5.100