Answer
0.6153
Work Step by Step
We need to find the z value:
$z = \frac{1200 - 1247.36}{100.96} = -0.47$
$z = \frac{1400 - 1247.36}{100.96} = 1.51$
$P(1200 \leq X \leq 1400) = P(-0.47 \leq z \leq 1.51) $
P ( Z < 1.51 ) − P (Z < −0.47 ) = P(z < 1.51) - (1 - P(z < 0.47))=
$0.9345 - (1 - 0.6808) = 0.9345 - 0.3192 = 0.6153$
