It would be nice to know what the problem was actually saying and asking. All I saw was a much of data and graphs.

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Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).

Yes it would be helpful
pink section is last week HW i did
this week i am using same data to
a)calculate R^2 which i got same answer as answerbook.
b) Prepare a normal probability plot of the residuals from the least squares model.
c) Plot the risiduals versus the fitted values and against X.
i got c) similar to answer book.
problem is b)
i standarized residual by dividing it by square root of sigma square.
then i used normsdist function in excel to get percentage of standarized residual d.
i plotted d vs percentage.
but the plot appears to be different.

what did i do wrong?

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

I've also got a PhD in pure maths, altough I don't work anywhere near academia at the moment.

Was your chart for 11-53(b) similar to the book solution? You've used the same technique for both, so it would seem odd if one is right and the other wrong. The chart technique seems like a reasonable heuristic for showing normality (or not, as the case may be).

What did the book answer look like?

what other students did was to use mini-tab to draw which was what answer book had.
i used what little math i know and used excel to draw the plot.
book answer was similar but didnt have funny curve that i had.
i can wait for my professor to reply to my homework... he will only decuct few points so really dont matter..
other than that plot i think i had everything else correct i think.

thank you for trying.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

Problem 1
Each month, a gas station sells 4,000 gallons of gasoline. Each time the parent company refills the stations's tanks, it charges the station $50 plus 70¢, per gallon. The annual cost of holding a gallon of gasoline is 30¢.
We are given that K = $50, h = 30¢/gallon/year, and D = 48,000 gallons/ year.
a. How large should the station's order be?
The EOQ is q* = (2KD/h)1/2
= (2(50)(48000)/.3)1/2
= 4000

b. How many order per year will be placed?
Order/Year = D/q* = 48000/4000 = 12

c. How long will it be between orders?
Length of a cycle = q*/D = 4000/48000 = 1/12 = one month

d. Would the EOQ Assumptions be satisfied in this situation? Why or Why not?
EOQ Assumption:
1. Demand is deterministic and occurs at a constant rate.
2. If an order of any size (say, q units) is place, an ordering and setup cost K is incurred.
3. The lead time for each order is zero.
4. No shortages are allowed.
5. The cost per unit-year of holding inventory is h
In real situation such as above demand will not be constand and lead time can not be zero.
Lead time not being zero also means that shortage may occur.

e. If the lead time is two weeks, what is the reorder point? If the lead time is ten weeks, what is the reorder point? Assume 1 week = 1/52 year.

For a 2-week lead time, reorder point = 48,000 x 2/52 = 1,846.15 gallons.
For a 10-week lead time, reorder point = 1,230.77 gallons.

can someone explain how leadtime of 10 week ordering point is less that 2 week ordering point?
answerbook said following:
If Leadtime = 10 weeks, then Leadtime demand > EOQ. Assume that an order arrives at time T=0. then an order must have been placed at T = -10. We know that an order is placed every 52/12 = 13/3 weeks. thus an order was place at T = 0 we will have 4000 gallons in stock, we know that at the reorder point T = 3 (and any other reorder point) we will have
4000-(3/52)48,000 = 1231 in stock.

reading that paragraph many times and can not understand what they said.

thanks in advance.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

Which part you don't understand? What it says is that you have be over two cycles ahead in your reorders, because the lead time is so long. And because of that, you can have less left than with a lead time of two weeks.

Another way of putting it is this: reorder point = (48000 x lead time in weeks / 52) Modulus 4000.

lead time of two gives (48000 x 2 / 52) Modulus 4000 = 1846.15
lead time of ten gives (48000 x 10 / 52) Modulus 4000 = 1230.77

Similarly a lead time of twenty would give 2461.54 etc

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understood ..thank you.
way you explain is much simpler than the answerbook.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

A drug store sells 30 bottles of antibiotics per week. Each time it orders antibiotics, there is a fixed ordering cost of $10 and a cost of $10/bottle. Assume that the annual holding cost is 20% of the cost of a bottle of antibiotics, and suppose antibiotics spoil and cannot be sold if they spend more than one week in inventory. When the drug store places an order, how many bottles of antibiotics should be ordered?
My answer is : If antibiotics spoil in one week and they sell 30 bottles per week only solution is to order 30 bottles everyweek. but not comfortable with this answer. can anyone do better?

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

I can't help but wonder if there's a typo and they meant to say that the antibiotics spoil after one month or year or something.

It is good to know that i am not the only one who think that way.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

Yeah, the problem as stated doesn't make a lot of sense. If they meant to say the antibiotics can't be stored for more than a year, then it makes more sense. It becomes a question of balancing the $10 fixed ordering cost against the 20% holding cost. You don't want to order too often, or you'll be hit by the ordering cost. But you don't want to place large, infrequent orders because then you have to store many bottles and pay a large holding cost.

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Poka King of the south east.

Excel is free software?

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I think I am so I think I am.

No, excel is not free. But there are free alternatives like openoffice which do most of the same things. Contrary to popular belief, you don't even need a huge bushy Linux beard to use them.

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Poka King of the south east.

OpenOffice is obsolete, AFAIK, and its successor is LibreOffice, available for free for OS X, Windows, and Linux.

/me strokes his huge bushy OS X beard

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“The only difference between me and a madman is that I’m not mad.” — Salvador Dali ★ Play a slooooow correspondence game with me on OGS?

StarOffice is even more obsolete, yet I use it every day on my Mac (which also has a paid-for MS Office)

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Offending ad removed

Cool

(BTW I also have the commercial MS Office for OS X since for my job I sadly find that most other programs don’t know to handle buggy RTF files well, and I often need to to/from RTF)

Also, I didn’t intend to put TheBigH down or criticize their mention of OpenOffice, just wanted to mention that there’s a successor to it that’s actually being worked on

Greetings, Tom


<edit>

Trivia (should it not be “trivium” since it’s just one?): StarOffice was originally developed by Marco Börries and his company, Star Division, just 35 km to the East of my place, in Lüneburg, Germany

</edit>

_________________
“The only difference between me and a madman is that I’m not mad.” — Salvador Dali ★ Play a slooooow correspondence game with me on OGS?

i tried this on my own for past 7 hours..
i know i am wrong on decision tree.
can someone help me with decision tree?
for problem #5 i know that answer is indifferent about hiring and i dont know how they got that.
for problem #4 EVPI can not be less than EVSI so i assume that my tree is wrong.

thank you in advance.

Solved it on my own...took me 10 hours to solve.
yea..i suck at math.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

no taker for previous question..

now i have simpler problem..(i think)

max v
st
v ≤ 1/2 x1 - x2 - x3

v ≤ -x1 + 1/2 x2 - x3

v ≤ -x1 -x2 + x3

x1 , x2 , x3 ≥ 0

how do i solve above LP?
It has been so long i forgot how to solve.
thank you in advance..

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson

Did your instructor suggest a method for solving linear programs? This problem is small enough that you should be able to test every vertex by hand, if that's all that's necessary.

can you guide me on how i can test every vertex?

i have similar example that is much simpler(with 2 variable) which was easily solved. one more variable throw me off.

_________________
"The more we think we know about
The greater the unknown"
Words by neil peart, music by geddy lee and alex lifeson