## Elementary Statistics (12th Edition)

a) $0.70$ b) $0.11$
a) We find: $μ=np=(64)(0.8)=51.2$ $σ=\sqrt{npq}=\sqrt{(64)(0.8)(0.2)}=32$ Hence, we find z: $z=\frac{49.5−51.2}{3.2}=−0.53$ Thus, using the table of z-scores, we can find that the corresponding probability is: $1−0.3=0.7$. b) We find the second z: $z=\frac{50.5−51.2}{3.2}=−0.22$ Thus, using the table of z-scores, we can find that the corresponding probability is: $0.41−0.3=0.11$.