Chapter 5 - Continuous Random Variables - Exercises 5.20 - 5.52 - Applying the Concepts - Basic - Page 242: 5.40b

$p(5\lt x\lt15)=.3460$

$z_0=\frac{x-\mu}{\sigma}=\frac{5-5.26}{10}=-.03$ $z_0=\frac{x-\mu}{\sigma}=\frac{15-5.26}{10}=.97$ According to table IV, page 773: $p(0\lt z\lt .03)=.0120$ $p(0\lt z\lt .97)=.3340$ $p(5\lt x\lt15)=p(-.03\lt z\lt.97)=p(-.03\lt z\lt0)+p(0\lt z\lt.97)=p(0\lt z\lt .03)+p(0\lt z\lt.97)=.0120+.3340=.3460$