Dr. Parnes has developed a standardized test that measures visual-spatial ability. When developing the test, Dr. Parnes gave the test to the same group of people at two separate administrations. The results were the same across both administrations of the test. We can conclude that Dr. Parnes' test _______________________________.
a.
needs more questions about visual-spatial ability
b.
is valid and reliable
c.
is valid
d.
is reliable