One of the ways in which the dental floss discussed in Exercise 5 can fail is if it snaps when pulled with a certain tension. Historically, only 2% of the tested floss snaps. Suppose boxes of size 50 are selected at random to be tested.
a) What is the standard deviation for the sample proportion from a box of 50?
b) What are the upper and lower 3s control limits?
c) How many packages in a box of 50 would have to fail for a process to be declared out of control using the 3s control limits?