Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,175 per hour and a standard deviation of $175.

Question

Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,175 per hour and a standard deviation of $175.
  
What is the operating cost for the lowest 10 percent of the airplanes? (Round z value to 2 decimal places. Omit the "$" sign in your response.)

PsyDAG · Answer

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.10) and its Z score.

Insert all data in above equation.