You want to compare the quality of several statistics textbooks.

(a) Identify two categorical variables and two quantitative variables that you would use to describe textbook quality. Give a reason for each of your choices.

So I think for the first categorical variable the materials like what is used to make the book and for the second the year it was published. Would those be considered categorical variables? I think I know the definition pretty well. And for the quantativ variable maybe the price? Or would that be categorical? And number of errors? Number of professors per college that use the textbook? Do any of those count as quantitative? Thank you for any helpful advice you might have!

By "what is used," are you referring to the type of paper, cover, etc. or the number of topics covered, the depth of coverage and the understandability of the material (is it user friendly?).

Price and number of pages would be quantitative. However, since usage by professors relies on other factors beside book quality -- selling ability of the book sales persons, what they are trying to "push," and personal relationships with the professors -- I would tend not to include this. However, professor evaluations of the book could be a qualitative factor.

I hope this helps. Thanks for asking.

To compare the quality of several statistics textbooks, you can consider the following variables:

Categorical Variables:
1. Materials Used: This is an appropriate categorical variable choice as it describes the type of materials used in the textbook's construction. For example, you may compare textbooks made of hardcover, paperback, or digital formats. The choice of materials can impact durability and user experience.

2. Year Published: This is also a suitable categorical variable choice as it represents the publication year of the textbooks. Different editions or versions may offer updated content, improved examples, or corrections. The publication year can be an important factor for those seeking the most recent and relevant information.

Quantitative Variables:
1. Price: The price of the textbooks can be considered a quantitative variable. It represents a measurable value, allowing you to compare the relative costs of the different textbooks. Lower or higher prices may indicate differing levels of affordability or the inclusion of additional supplementary materials.

2. Number of Errors: The number of errors present in a textbook can be quantified and used as a measure of quality. By comparing the frequency of errors, you can assess the accuracy and attention to detail in the content. A lower number of errors may indicate a higher-quality textbook.

However, the number of professors per college that use a particular textbook is not a quantitative variable. It is categorical since it represents discrete categories (e.g., textbooks used by 0-5 professors, 6-10 professors, etc.). Similarly, while the number of errors is quantitative, it would be difficult to measure it without actually reviewing each textbook.

Remember, the choice of variables may vary depending on the specific aspects of textbook quality you are interested in evaluating.