Social security and medicare are

progressive taxes.
payroll taxes.
local taxes.
corporate taxes.

In order to conduct a one-sample proportion z-test, the following conditions should be met: The data are a simple random sample from the population of interest. The population is at least 10 times as large as the sample. n⋅p≥10 and n⋅(1−p)≥10 , where n is the sample size and p is the true population proportion.

hope it helps.