In: Statistics and Probability
A manufacturing process produces 6.6% defective items. What is the probability that in a sample of 40 items: a. 12% or more will be defective? (Round the z-value to 2 decimal places and the final answer to 4 decimal places.) Probability
b. less than 2% will be defective? (Round the z-value to 2 decimal places and the final answer to 4 decimal places.) Probability
c) more than 12% or less than 2% will be defective? (Round the z-value to 2 decimal places and the final answer to 4 decimal places.) Probability
Given : n=40 , p=6.6%=0.066 , q=1-p=0.934
By using the normal approximation ,
a) Now ,
; From standard normal probability table
Therefore , the probability that the 12% or more will be defective is 0.0853
b) Now ,
; From standard normal probability table
Therefore , the probability that less than 2% will be defective is 0.1210
c) Now ,
; From standard normal probability table
Therefore , the probability that more than 12% or less than 2% will be defective is 0.2063