Chapter 5 - Continuous Random Variables - Exercises 5.20 - 5.52 - Learning the Mechanics - Page 242: 5.31b

$p(6\leq x\leq10)=.3023$

$z=\frac{x-\mu}{\sigma}=\frac{10-11}{2}=-.5$ $z=\frac{x-\mu}{\sigma}=\frac{6-11}{2}=-2.5$ $p(6\leq x\leq10)=p(-2.5\leq z\leq-.5)=p(-2.5\leq z\leq0)-p(-.5\lt z\leq0)=p(0\lt z\leq2.5)-p(0\lt z\leq.5)=.4938-.1915=.3023$ According to Table IV, page 773: $p(0\lt z\leq.5)=.1915$ $p(0\lt z\leq2.5)=.4938$