In the middle ages, people accused of being witches were often tested by being dunked in a river or pond. If they floated to the surface they were condemned as witches. If they sank and drowned they were posthumously acquitted. This test obviously lacks:

a) reliability.
b) standardization.
c) validity.
d) bias.

ANS: C, These "tests" do not actually assess whether the test-taker is or is not a witch.