Question 1031952
The point estimate is 850/3000=0.28
The 99%CI is 
2.576+/- sqrt(.28)(.72)/sqrt(3000)=0.021
to two decimal places, the 99%CI is (0.26,0.30)
We don't know the true proportion of calls that will require towing, but we are highly confident the number resides in the range (0.26,0.30).