Using samples of 190 credit card statements, an auditor found the following:Use Table-A.
Sample 1 2 3 4 Number with errors 4 2 6 8________________________________________ a. Determine the fraction defective in each sample. (Round your answers to 4 decimal places.) Sample Fraction defective1
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 .047 and .006 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 .047 and .006, is the process in control? yesno
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? YesNo