Using the z-distribution, as we are working with a proportion, it is found that:
a) The population proportion is of 0.625.
b) The interval is (0.586, 0.664).
<h3>What is a confidence interval of proportions?</h3>
A confidence interval of proportions is given by:

In which:
is the sample proportion.
In this problem, we have a 99% confidence level, hence
, z is the value of Z that has a p-value of
, so the critical value is z = 2.575.
The sample size and the population proportion are given, respectively, by:

Hence, the bounds of the interval are given by:


More can be learned about the z-distribution at brainly.com/question/25890103