Question 1170285
Ho: p men >= p women
Ha: p men < p women
left tailed, because we suspect p men < p women
men is 20/80 or 0.25
women is 12/40 or 0.3
the critical value is z<-1.96
the numerator is the difference between 0.25 and 0.3 or -0.05
the denominator is sqrt ((.25.*.75/80)+(.3.*.7/40))=sqrt(0.0075)=0.0868
z is -0.58.Fail to reject; insufficient evidence to show a difference.