Question

Using samples of 194 credit card statements, an auditor found the following:
Use Table-A.

Sample	1	2	3	4
Number with errors	3	1	6	12

a. Determine the fraction defective in each sample. (Round your answers to 4 decimal places.)
  

Sample	Fraction defective
1
2
3
4

b.If the true fraction defective for this process is unknown, what is your estimate of it? (Round your answer to 1 decimal place. Omit the "%" sign in your response.)

Estimate              %

c. What is your estimate of the mean and standard deviation of the sampling distribution of fractions defective for samples of this size? (Round your intermediate calculations and final answers to 4 decimal places.)
  

Mean
Standard deviation

d.What control limits would give an alpha risk of .03 for this process? (Round your intermediate calculations to 4 decimal places.Round your "z" value to 2 decimal places and other answers to 4 decimal places.)
  

z =  ,     to  

e.What alpha risk would control limits of .0470 and .0098 provide? (Round your intermediate calculations to 4 decimal places.Round your "z" value to 2 decimal places and "alpha risk" value to 4 decimal places.)
  

z =  , alpha risk =  

f.Using control limits of .0470 and .0098, is the process in control?

• no

• yes

g.Suppose that the long-term fraction defective of the process is known to be 2 percent. What are the values of the mean and standard deviation of the sampling distribution? (Round your intermediate calculations and final answers to 2 decimal places.)

Mean
Standard deviation

h.Construct a control chart for the process, assuming a fraction defective of 2 percent, using two-sigma control limits. Is the process in control?

• Yes

• No

Answer 1

1)

2)

3)

4)