The college newspaper of a large midwestern university conducts a
survey of faculty and students on campus to determine whether they
feel there is adequate student parking on campus. An SRS of 100
faculty and a separate SRS of 400 students is selected. 50 of the
faculty and 320 of the students say there is not adequate parking on
campus.

The sampling distribution for the difference in the sample proportions,
p1-p2, has a standard deviation equal to what?

Faculty and students often have separate parking lots.  So faculty may
have adequate parking even if students do not.