Question

If the mesh tension of individual monitors follows a Normal distribution, we can describe capability by giving the percent of monitors that meet specifications. The old specifications for mesh tension are 100–400 mV. The new specifications are 150–350 mV. Because the process is in control, we can estimate that tension has mean 275 mVand standard deviation 38.4 mV

(a) What percent of monitors meet the old specifications? (Enter your answer rounded to two decimal places.)

percent of monitors: %

(b) What percent meet the new specifications? (Enter your answer rounded to two decimal places.)

percent of monitors: %

Answer 1

Solution: We are given:

(a) What percent of monitors meet the old specifications?

Answer: The old specifications are:

We can use the z-score formula to find the percent of monitors that meet the old specifications.

Now using the standard normal table, we have:

  

Therefore, the percent of monitors is:

(b) What percent meet the new specifications?

Answer: The new specifications are:

We can use the z-score formula to find the percent of monitors that meet the old specifications.

Now using the standard normal table, we have:

  

Therefore, the percent of monitors is: