Question 1159166
mean is 150*0.15=22.5
variance is np(1-p)=22.5*0.85=19.125
sd is sqrt (V)=4.373

fewer than 20 no shows means < 19.5 using continuity correction factor
z<(19.5-22.5)/4.373
z<-0.686
that probability is 0.2464

(exact is 0.2509)