Stats 6590 Project
Diamond Pricing Data

Now you are ready to earn some big money as a statistical consultant. You have been hired by a large jewelry company to propose a sensible pricing model for diamond stones based on data pertaining to their weight (in carats), their colour and clarity. Another important variable (cut), will not be considered. In particular, the jewelry company is interested in the relative worth of the different grades of colour and clarity and whether differences in prices can be attributed to three different certification groups. A copy of the dataset is available through our course webpage:
http://www.math.mun.ca/~sneddon/st6590
If you plan on using Splus to do your data analysis, you can access the data in Splus by typing:

 attach("/users/math/faculty/sneddon/DATA")

The data is in the file diamonds.dat SOURCE: The data appeared in Singapore's Business Times edition of February 18, 2000.

Data Description

The columns of the dataset are described below. The weight of a diamond stone is indicated in terms of carat units. One carat is equivalent to 0.2 grams. All other things being equal, larger diamond stones command higher prices in view of their rarity. Diamonds have inclusions (marks) only visible under a jeweler's magnifying glass or a microscope. Diamonds with no inclusion under a loupe with a 10 power magnification are labelled IF (internally flawless). Lesser diamonds are categorised in descending order as very very slightly imperfect VVS1 or VVS2 and very slightly imperfect VS1 or VS2. The most prized diamonds display colour purity. They are not contaminated with yellow or brown tones. Top colour purity attracts a grade of D. Subsequent degrees of colour purity are rated E, F, G, etc. Certification groups assess diamond stones and provide each of them with a certificate listing their caratage and their grades of clarity, colour and cut. Three of these groups are the Gemmological Institute of America (GIA), International Gemmological Institute (IGI) and Hoge Raad Voor Diamant (HRD). Their reputations could be a factor in the pricing of the diamond stones.

1. Carat - Weight of diamond stones in carat units
2. Colour - D, E, F, G, H or I
3. Clarity - IF, VVS1, VVS2, VS1 or VS2
4. Certification Body - GIA, IGI or HRD
5. Price (Singapore $)