ABSTRACT
The standard error of βˆ1 is σ = = =β s cˆ 10.365959 0.012523 0.360296ˆ 221 . g. For confidence coefficient 0.90, α = 0.10 and α = =/2 0.10/2 0.05. From Table 7,
Appendix B, with = − = − =df n 2 6 2 4, =t 2.1320.05 . The 90% confidence interval is
( ) ( )β ± σ ⇒ ± ⇒ ± ⇒α βtˆ ˆ 0.9665 2.132 0.360296 0.9665 0.7682 0.1983, 1.73471 /2 ˆ1 We are 90% confident that the mean apparent porosity percentage will increase
between 0.1983 and 1.7347 percent for every one micro-meter increase in mean pore diameter of a brick.
