As part of a larger project to study the behavior of stressed-skin panels, a structural component being used extensively in North America, an article reported on various mechanical properties of Scotch pine lumber specimens. Data on the modulus of elasticity (MPa) obtained 1 minute after loading in a certain configuration and 4 weeks after loading for the same lumber specimens is presented here.
Observation 1 min 4 weeks Difference 1 10,450 9,130 1320 2 16,620 13,250 3370 3 17,500 14,720 2780 4 15,480 12,710 2770 5 12,960 10,120 2840 6 17,260 14,570 2690 7 13,400 11,220 2180 8 13,900 11,100 2800 9 13,630 11,420 2210 10 13,210 10,940 2270 11 14,370 12,110 2260 12 11,700 8,640 3060 13 15,470 12,590 2880 14 17,840 15,090 2750 15 14,060 10,550 3510 16 14,760 12,230 2530
Calculate an upper confidence bound for the true average difference between 1-minute modulus and 4-week modulus; first check the plausibility of any necessary assumptions. (Use 𝛼 = 0.05. Round your answer to two decimal places.)
MPa
Interpret your upper confidence bound.
We are 95% confident that the true mean difference between 1-minute modulus and 4-week modulus is never the upper bound. We are 95% confident that the true mean difference between 1-minute modulus and 4-week modulus is at least the upper bound. We are 95% confident that the true mean difference between 1-minute modulus and 4-week modulus is at most the upper bound. We are 95% confident that the true mean difference between 1-minute modulus and 4-week modulus is exactly the upper bound.
=0.05.)
. The data suggests a significant mean difference in the average number of accidents after information was added to road signs.
