Answer:0.051
Step-by-step explanation:
p=70%=0.70
The standard deviation of the sampling distribution of the sample proportion is the square root of the product of p and q divided by the sample size n:
=squareroot(pq/n)
=squareroot(p(1-p)/n)
=squareroot(0.70(1-0.70)/80)
=0.051