The analyst in the Dorben Reference Library decides to use the work sampling technique to establish standards. Twenty employees are involved. The operations include cataloging, charging books out, returning books to their proper location, cleaning books, record keeping, packing books for shipment, and handling correspondence. A preliminary investigation resulted in the estimate that 30 percent of the time of the group was spent in cataloging. How many work sampling observations would be made if it were desirable to be 95 percent confident that the observed data were within a tolerance of ±10 percent of the population data? Describe how the random observations should be made.

The following table illustrates some of the data gathered from 6 of the 20 employees. The number of volumes cataloged equals 14,612. From this data, determine a standard in hours per hundred for cataloging. Then design a control chart based on three-sigma limits for the daily observations.

                                                                                  Operators

Item                                              Smith          Apple      Brown     Green     Baird         Thomas

Total hours worked                        78                80             80           65          72               75

Total observations (All elements) 152              170            181         114        143             158

Observations involving cataloging 50                55              48           29         40               45

Average rating                                90                95            105           85        90               100