## Elementary Statistics (12th Edition)

$z_{1}=\frac{value-mean}{standard \ deviation}=\frac{4.2-4.577}{0.382}=-0.99$ $z_{2}=\frac{value-mean}{standard \ deviation}=\frac{5.4-4.577}{0.382}=2.15$ Using the table, the probability of z being between -0.99 and 2.15 is equal to the probability of z being less than 2.15 minus the probability of z being less than -0.99, which is: 0.9842-0.1611=0.8231=82.31%.