The correct answer is:
-1.5.
Explanation:
The formula for a z-score is
[tex] z=\frac{X-\mu}{\sigma} [/tex], where X is our test value, μ is the mean, and σ is the standard deviation.
Using our information, we have:
[tex] z=\frac{28000-34000}{4000}=\frac{-6000}{4000}=-1.5 [/tex]