Example 7.11 gave data on the modulus of elasticity obtained 1 minute after loading in a certain configuration.

The cited article also gave the values of modulus of elasticity obtained 4 weeks after loading for the same lumber specp 5 .033

(p 5 0.003, t value 5 3.65)

5 2227.8(96.6)

Mean (6 SD) 5 2145.3(68.0)

Calculate and interpret 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.