Question 979782
One sample proportion
Ho=p<0.25
Ha=p>=0.25
alpha =0.05 (choose)
one-tail test
critical value: z>1.645
(336/1200)=0.28

standard error: sqrt{ (0.25)*(0.75)/1200}=0.0125

z=(0.28-0.25)/0.0125  = 2.4.  This exceeds the critical value and the null hypothesis is rejected with p,0.01.