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Statistical Analysis of Diamond Data

O Perform some quick research (likely on the web) to describe color, quality, and certification of diamonds.

o Respond to the following (based on the data in the Excel file) and support each with some reference to a statistical tool or graphical analysis.

(1) If someone wanted a large but inexpensive diamond, what color, quality, and certification would offer this?

(2) What combination of color, quality, and certification appears to be the most expensive?

(3) Develop a model (equation) that could be used to predict the cost of a diamond. Note that this could be an overall model that predicts the cost of a diamond just based on its weight, or it could require the user (likely a diamond buyer) to share color, quality, and certification preferences. You may even develop multiple models but no more than three. If you develop multiple models, discuss why. Note any limitations or weaknesses of the model(s).

See attached files: "Analysis of the data for Diamonds" is the problem description; "Diamonds" is the data.


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 Part Three is an analysis of the data the Diamonds.xls file.
o Provide a bulleted outline of the process, tools, and techniques used during your analysis. Note how or why you selected the tool or technique.
o Perform some quick research (likely on the web) to describe Color, Quality, and Certification. Don't spend a lot of time here, just ground yourself in what the various values for Color, Quality, and Certification mean. There are a lot of retail sites that offer reasonable summaries. Citations and references are not required but may be helpful.

Here is information I found at Color is obviously described under "Color", quality is described under clarity, and certification is described after color. I found more information about quality at and put that information after color:
Refers to the presence of inclusions in a diamond.
Every diamond is unique. Nature ensures that each diamond is as individual as the person who wears it. Naturally-occurring features?know as inclusions?provide a special fingerprint within the stone. Inclusions are natural identifying characteristics such as minerals or fractures, appearing while diamonds are formed in the earth. They may look like tiny crystals, clouds or feathers.
To view inclusions, jewelers use a magnifying loupe. This tool allows jewelers to see a diamond at 10x its actual size so that inclusions are easier to see. The position of inclusions can affect the value of a diamond. There are very few flawless diamonds found in nature, thus these diamonds are much more valuable.
Inclusions are ranked on a scale of perfection, known as clarity, which was established by the Gemological Institute of America (GIA). The clarity scale, ranging from F (Flawless) to Included (I), is based on the visibility of inclusions at a magnification of 10x.
Some inclusions can be hidden by a mounting, thus having little effect on the beauty of a diamond. An inclusion in the middle or top of a diamond could impact the dispersion of light, sometimes making the diamond less brilliant.
The greater a diamond's clarity, the more brilliant, valuable and rare it is?and the higher it is on the Diamond Quality Pyramid.
Refers to the degree to which a diamond is colorless.
Diamonds are found in almost every color of the rainbow, but white-colored diamonds remain most popular.
Diamonds are graded on a color scale established by the Gemological Institute of America (GIA) which ranges from D (colorless) to Z. Warmer colored diamonds (K-Z) are particularly desirable when set in yellow gold. Icy winter whites (D-J) look stunning set in white gold or platinum.
Color differences are very subtle and it is very difficult to see the difference between, say, an E and an F. Therefore, colors are graded under controlled lighting conditions and are compared to a master set for accuracy.
Truly colorless stones, graded D, treasured for their rarity, are highest on the Diamond Quality Pyramid. Color, however, ultimately comes down to personal taste. Ask a jeweler to show you a variety of ...

Solution Summary

Information on color, quality, and certification of diamonds is provided. Scatterplots and regression analyses are used to answer the three questions based on the data in the attached Excel file.