1. (25 points) It is proposed to develop X and R charts to control the diameter of a product. The following data have been collected for some samples.

Sample # diameter values in sample

1 10.1, 10.3, 10.0, 9.9, 10.3, 10.2

2 9.8, 10.2, 10.1, 10.2, 9.9, 9.9

3 10.3, 9.8, 10.2, 9.9, 9.8, 9.9

4 9.9, 9.9, 10.1, 9.8, 10.3, 10.5

5 10.2, 10.1 10.3, 9.8, 9.9, 10.2

_ _

Construct X and R charts for this process and plot the X and R values of all the above samples in those charts.

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2. (Total 25 points) The Garden-variety flower shop uses 9600 clay pots per year. The pots are purchased at $25 each. The annual holding costs are estimated to be 5.2% of unit cost, and ordering costs are $60 per order.

(A) (10 points) Determine the economic ordering quantity (EOQ).

(B) (3 points) If EOQ is used for ordering, what will be the total holding cost per year?

(C) (2 points) What is the length of ordering cycle in days?

(D) (10 points) What will be additional cost per year if the manager adopts a policy of ordering 800 units per order?

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3. (Total 25 points) The demand for chair is 2000 per month. Each chair costs $55. The ordering cost per order is $30. The monthly holding cost per chair is 0.8 dollars.

(a) (8 points) Compute EOQ.

(b) (3 points) How many orders will be placed in a YEAR if EOQ is used for ordering quantity?

(c) (7 points) What will be the total cost per month by ordering a quantity equal to EOQ every time?

(c) (7 points) What will be the total cost per month by adopting a policy of ordering 500 chairs per order instead of ordering EOQ?

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4. (Total 25 points) It is given that K and L are the immediate upper level items for P in the product structure (BOM) and each unit of K needs 5 units of P and each unit of L needs 6 units of P. P is not required by any other items in the product structure. Given the following planned order release (PRL) for K and L, obtain the gross requirements (GR) for P and then obtain PRL for P in the MRP table if P has a scheduled receipt of 200 in period 2 and 150 in period 5, and on-hand inventory of 800 units. The lead times for K, L, and P are 2, 1, and 1 periods respectively.

Periods

1 2 3 4 5 6 7

K: LT= PRL 180 90 110 90 100

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L: LT= PRL 95 115 100 80

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P: LT= GR_________________________________________________________

SR_________________________________________________________

OH_________________________________________________________

NR_________________________________________________________

POR________________________________________________________

PRL

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7 points for obtaining GR of P in different periods

18 points for obtaining the rest of the values in the table for P in different periods.