Answer: The point estimate of the proportion of resident who are against expanding the airport is 0.745.
Explanation:
Since we have given that
A reporter determined that the true proportion of residents in a city who are against expanding the airport is likely in the interval (0.71, 0.78).
So, we need to find the point estimate of the proportion of residents who are against expanding the airport.
So, Point estimation of the proportion of resident would be

Hence, the point estimate of the proportion of resident who are against expanding the airport is 0.745.