Use the following table to answer the question(s) below.

-A producer of contact lenses regularly takes samples of 100 lenses and inspects them for scratches. If a lens has a single scratch, it cannot be sold. The results of 10 samples are shown below: What are the lower and upper 3-sigma control limits?
A) (-0.021, 0.012)
B) (-0.021, 0.000)
C) (0.012, 0.035)
D) (0.000, 0.035)
E) (0.000, 0.049)

Question

Use the following table to answer the question(s) below.
 
-A producer of contact lenses regularly takes samples of 100 lenses and inspects them for scratches. If a lens has a single scratch, it cannot be sold. The results of 10 samples are shown below: What are the lower and upper 3-sigma control limits?
A) (-0.021, 0.012) 
B) (-0.021, 0.000) 
C) (0.012, 0.035) 
D) (0.000, 0.035) 
E) (0.000, 0.049)

Quizplus · Accepted Answer

The lower 3-sigma control limit is the mean minus 3 times the standard deviation, and the upper 3-sigma control limit is the mean plus 3 times the standard deviation. The mean is 0.012 and the standard deviation is 0.011, so the lower 3-sigma control limit is 0.012 - 3(0.011) = 0.000 and the upper 3-sigma control limit is 0.012 + 3(0.011) = 0.049.

Use the Following Table to Answer the Question(s) Below