rev: 02_06_2012
rev: 03_15_2012 http://lectures-auth.mhhe.com/connect/0073525251/hints/hint_10-28.html check my workeBook Link View Hint #1references
Problem 10-3
Checkout time at a supermarket is monitored using a mean and a range chart. Six samples of n = 20 observations have been obtained and the sample means and ranges computed: |
Sample | Mean | Range | Sample | Mean | Range | 1 | 3.06 | .42 | 4 | 3.13 | .46 | 2 | 3.15 | .47 | 5 | 3.06 | .46 | 3 | 3.11 | .41 | 6 | 3.09 | .45 | |
Factors for three-sigma control limits for and R charts |
| | -------------------------------------------------
FACTORS FOR R CHARTS | Number of Observations in Subgroup, n | Factor for
Chart,
A2 | Lower
Control Limit,
D3 | …show more content…
| Is the process in control? | | | | | Yes | | No | |
Problem 10-4
Computer upgrades have a nominal time of 80 minutes. Samples of five observations each have been taken, and the results are as listed. |
-------------------------------------------------
SAMPLE | 1 | 2 | 3 | 4 | 5 | 6 | 79.2 | 80.5 | 79.6 | 78.9 | 80.5 | 79.7 | 78.8 | 78.7 | 79.6 | 79.4 | 79.6 | 80.6 | 80.0 | 81.0 | 80.4 | 79.7 | 80.4 | 80.5 | 78.4 | 80.4 | 80.3 | 79.4 | 80.8 | 80.0 | 80.6 | 80.1 | 80.8 | 80.6 | 78.8 | 81.1 | |
Factors for three-sigma control limits for and R charts |
| | -------------------------------------------------
FACTORS FOR R CHARTS | Number of Observations in Subgroup, n | Factor for
Chart,
A2 | Lower
Control Limit,
D3 | Upper
Control Limit,
D4 | 2 | 1.88 | 0 | 3.27 | 3 | 1.02 | 0 | 2.57 | 4 | 0.73 | 0 | 2.28 | 5 | 0.58 | 0 | 2.11 | 6 | 0.48 | 0 | 2.00 | 7 | 0.42 | 0.08 | 1.92 | 8 | 0.37 | 0.14 | 1.86 | 9 | 0.34 | 0.18 | 1.82 | 10 | 0.31 | 0.22 | 1.78 …show more content…
| How much could the company save annually if the setup cost could be reduced to $28 per run? (Round your intermediate calculations and final answer to 2 decimal places. Omit the "$" sign in your response.) |
Savings would be | $ |
6.
value:
10 points Problem 13-14
A jewelry firm buys semiprecious stones to make bracelets and rings. The supplier quotes a price of $8.2 per stone for quantities of 600 stones or more, $9.5 per stone for orders of 400 to 599 stones, and $10 per stone for lesser quantities. The jewelry firm operates 183 days per year. Usage rate is 25 stones per day, and ordering costs are $48. |
a. | If carrying costs are $2 per year for each stone, find the order quantity that will minimize total annual cost. (Round your intermediate calculations to the nearest whole number.) |
Order quantity | stones |
b. | If annual carrying costs are 23 percent of unit cost, what is the optimal order size? (Round your intermediate calculations to the nearest whole number.) |
Optimal order size | stones |
c. | If lead time is 4 working days, at what point should the company reorder? (Round your intermediate calculations to the nearest whole number.) |
Reorder quantity | stones