This document will contain notes to the class regarding assignments and other material. Check back often. Many of the things here were probably also written in the notes to class in the Spring 2006 semester, you may want to check there for a heads-up.
October 27, 2006
I updated the practice exams so that they are from the Spring 2006 semester rather than the Fall 2002 semester. These should be closer to what your exams will looke like.
I need specifics on the questions for #1. Don't say "it increases or decreases" or "it gets bigger when you add and smaller when you subtract" but say how.
The way this will appear on the test is like this:
I will give you the mean, median, range, st. dev, and variance ... but not the original numbers ... for a set of data and then ask you to tell me what the new mean will be if you subtract 50 from all the numbers or multiply all the values by 7.
Here's an example of what it will look like on the test.
| Mean | Median | Range | St. Dev | Variance | |
|---|---|---|---|---|---|
| x | 40 | 45 | 170 | 20 | 400 |
| x-50 | |||||
| 7x |
Saying "the mean gets smaller when you subtract 50 from all the data" doesn't help you answer the question.
Saying something like "when adding/subtracting a constant to/from the data, you add/subtract that same constant to/from the mean and median" is a much better answer and explains the relationship much more thoroughly and in a useful manner. Do not refer to the 50, but be generic and call it a "constant". That way, it will work for other cases.
The best way to find the variance is NOT to use Minitab. You won't have the data available to you, so Minitab will be of no use. The question was actually supposed to be how multiplying or dividing by a constant affects the variance, I forgot to update the Word file that I put on the PublicFiles drive.
Always use the ( ) template from the toolbar, or use the keyboard shortcut ctrl-9, when you need to use parentheses. Do not type the ( and ) separately. The parentheses that are typed from the keyboard don't grow with the expression inside. To see an example of this, type ( and then hit ctrl-f for fraction. Notice the ( stays small and looks ugly. Now erase all that and press ctrl-9 or choose ( ) from the templates. Now press ctrl-f for fraction and notice how the parentheses grow.
When you have an equation, the entire equation should go in the equation object, not just the part you can't do with the word processor. Many of you are taking an equation like "s2 = 6.7" and using the equation editor / MathType for just the s2 part. The "= 6.7" should be in there as well. One goal of the notations is to get you to learn to communicate using the language of mathematics and that involves recognizing the proper way to write things, not just some computer trick to get the s2. The same thing applies to equations that begin "Variation =" or "Variance =". Those should be entered with the equation editor.
When you have chained equalities like "s = √6.7 ≈ 2.59", you should include all three items in one equation object.