Question 1120541
Yes,random sample with population defined as a one sample proportion test
Ho: p is >=0.75
Ha: p is < 0.75
alpha is 0.05 P{reject Ho|Ho true}
test stat is z=(p hat-p)/sqrt (p*(1-p)/n); p hat is 85/120, the point estimate, or 0.708
Critical value z<-1.645 one tail test
z=(0.708-0.75)/sqrt (0.75*0.25/120); sqrt term is 0.0395
=-0.042/ 0.0395
=-1.05
Fail to reject, p-value 0.15.  Insufficient evidence to say that the true proportion is less than 0.75.