Posted by Kira on .
The inner diameter of a piston is normally distributed with mean of 10 cm and standard deviation 0.03cm
a)below what value of inner diameter will fall fifteen percent of the piston rings?

Math 
PsyDAG,
Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.15) related to a Z score. Insert the values into the above equation.