Suppose that a software development team released an update to one of their mobile applications after receiving complaints
about the previous version from 9.8% of their customers. A few weeks after the update was released, the development team
wanted to know if fewer customers had complaints. The team selected a random sample of 250 customers and found that 16
of them submitted complaints about the application after the update was released.
The team wants to use a one-sample z-test for a population proportion to see if the proportion of customers with complaints,
has decreased since they released the update. For this test, they plan to use a significance level of a = 0.05.
P.
What is the z-test statistic?