Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,325 per hour and a standard deviation of $240.

Question

Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,325 per hour and a standard deviation of $240.
What is the operating cost for the lowest 5 percent of the airplanes?

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 (.05) and its Z score. Put values into above equation and solve for raw score.

Anonymous · Answer

1549