Poindexter's Rat-Freeze

Poindexter LeMans sat at his Louis XIV desk and looked at the garage monitor. Sure enough there was his Bugatti Veyron 16.4 parked snuggly in the middle of his other 50 cars, Sure $1,700,000 is lot to spend on one car, but how else am I going to get to work on time when my sea-side palatial home is almost 20 miles from the office and I only have 6 free minutes a day to make the trip?

As you might have guessed Poindexter had a very successful business career going or else he wouldn't have had all those expensive trappings, and probably would have been fired for goofing off. And you'd have guessed right...he was rich. In fact, he never bought a lottery ticket because he was afraid he might win and he was running out of places to put the money he already had.

And he owed all his wealth to rats ... dirty disease-spreading rats. Poindexter had always enjoyed killing rats ever since he used to beat their brains out with a Stanley 54-716 jacketed graphite ball-peen hammer at the orphanage. The Jesuit Priests who ran the place taught Poindexter to take pride in his work and to always use the best tool for the job. They had given him the hammer on his 6th birthday and he couldn't have been happier; he killed 52 rats within the first 24 hours. By the time he was 10 years old environmentalists feared that at the rate he was going rats would become extinct within the next decade. Fortunately (for rats at least) he took several years off rat killing to get a college education.

After earning his Ph.D. in astrophysics at Cal Tech, he began recklessly experimenting with a new rocket fuel and accidentally discovered that rats could be flash frozen with liquid oxygen (LOX). This accident involved the tragic loss of a dedicated and hard-working lab rat he had named "Stanley" (after his beloved hammer), but yielded a clean method of killing rats.

This flash freezing of rats avoided "the" problem in rat extermination. The old way of killing rats was to put out poison. No matter how lethal the poison, if a big enough rat ate it, it would still have time to escape to its home in the wall before dying. It would then slowly decompose causing a horrific stench for perhaps months as its inaccessible decaying carcass turned slowly into guacamole.

With Poindexter's Rat-Freeze trap, even a giant cat-sized rat couldn't get more than an inch before it was frozen as solid as a popsicle at the North Pole in January (or at the South Pole in July). Poindexter's advertising proudly proclaimed "Less than an inch or I'll give you your money back and eat the rat."

But now Poindexter was worried. Recently one especially gigantic rat had moved just over a full inch before its frosty demise. He ate the rat, as promised, but it was prepared in a nice béarnaise sauce by his private chef so it wasn't too bad...the bones were a little crunchy, but not bad...sort of like Buffalo Wings.

Poindexter's real fear was that this event might not be isolated. If another rat was able to move more than an inch, the news would spread and sales might suffer; his customers, like himself, demanded exactly what was promised: an inch rat movement maximum. Furthermore, although the rat he ate had been tolerable, he didn't really want to eat more than one rat every other day. And finally, Poindexter needed the cash from his sales to buy a villa he had his eye on in Monte-Carlo, and his Gulfsteam G650 was purchased last May and he was thoroughly embarrassed whenever one of his billionaire friends saw him flying around in a jet that was almost half a year old.

Poindexter thought the failure might have something to do with quality problems at the new supplier of his LOX spray nozzles. Specifically, he suspected that the supplier was not properly holding a key diameter at the throat of the nozzle.

Poindexter had two types of data available to work with in exploring this issue. The first dataset consisted of 50 individual nozzle diameters produced by the supplier. That data is normally distributed, and can be found on the first sheet in the Excel file (the sheet labeled "50 Throat Diameters"). Poindexter's specification on that diameter was 0.1000 plus or minus 0.0050. Assume that this data was taken at a time when the process was definitely under control.

The second dataset (on the second page in the Excel file labeled "20 Samples of Size 5") is the last 20 samples of 5 nozzle throat diameters. Each horizontal row represents one sample. Each row first gives the five observations that make up the sample (in columns B to F), then gives the sample's mean (in column H) and range (in column I). The 20 samples are listed in the order in which they were taken. That is, sample 1 (the first row) was taken first, sample 2 (the second row) was taken second, etc. Do NOT assume that this data was taken when the process was definitely under control.

Assume that there is nothing wrong with the design of the Rat Freeze. Either the problem is due to the supplier or there really isn't a problem (the rats that didn't die instantly were just a fluke). You need to find out what the truth is, is there a problem or not?
Answer the following questions in a Word document, and enclose a copy of the Excel spreadsheet that you received, showing your work calculations and graphs. Send both files to me via email with "Rat Freeze" the subject of the email.

Make certain you double space your answers. Also label your answers so I know which answer goes with which question.

All answers must be in proper English. That is, your grammar, spelling, and punctuation must be correct. Points will be lost if your answers are not in proper English. Use the rubric as a guide for how your paper will be assessed by AACSB standards.

1. Before you do any analysis, state what sort of process problems the supplier might have. Do not determine if a problem really exists. I only want you to say what sort of problem could possibly exist. If you have trouble answering this question just look at the tests in chapter 10 and ask yourself what each one is for. Use as many paragraphs to answer this question as you have process problems. That is, if you find 2 possible problems, write your answers in 2 paragraphs.

2. For each type of possible problem you identified in your answer to question one do some analysis (you decide what to do) using one or both of the 2 databases to see if the problem really does exist. Write one paragraph for each type of problem, say what data and analysis you used to see if it really exists, and say what your conclusion is.

3. In answering question 2, did you do a run test? If yes, why? If no, why not?

Attachment:- poindexter_rat_freeze.rar