A civil service exam yields scores which are normally distributed with a mean of 81 and a standard deviation of 5.5. If the civil service wishes to set a cut-off score on the exam so that 15% of the test takers fail the exam, what should the cut-off score be? Remember to round your z-value to 2 decimal places.
Choose one answer.
A. 75.28
B. 86.72
C. 60.24
D. 64.56
E. None of the above

If 15% fail, then 85% pass.

Look up the z score that corresponds to .15 in the z table.

Then, use the formula

to solve for x by subbing in all

the known values.

If you have a z table giving you the left tail probability, look for 0.85 probability instead.

Anyway, if you sketched the bell shape curve, you should be able to guess what is the most sensible answer.