Week 14

Topics

We will cover the first half of chapter 11 this week.

Normally, we would have HW 11 this week, and Exam 4 next week. However, the university frowns on exams during dead week. So, we will have the exam this week, and HW next week. This means that the material from this week will not be on the exam, but it will be on the final exam.

Overview of the Sections

Section 11-1 deals with graphing data. You will learn how to read and produce vertical bar charts (column charts), horizontal bar charts, and pie charts. I assume that most of you already know how to read them. You need to learn how to produce these charts in Excel, but that is very easy. We have already done graphing in Excel in chapter 2. You do the same thing here, you just select a different kind of graph from the menu that Excel offers. This will be covered in class next week.

You will also learn how to divide large sets of numbers into classes. For example, you could take 100 test scores, decide where the grade cutoffs are, and divide the range of scores into 5 intervals corresponding to A, B, C, D, F. Counting the number of scores in each class produces a frequency table. When you plot the frequency table as a vertical bar chart, that is called a histogram. Excel actually has tools for producing frequency tables, but we won't use them in this class. You can skip the frequency polygons in section 8-2, but look at the cumulative frequency tables.

The other two sections we cover will be very important for any future statistics courses you may be taking. When a statistician looks at a frequency table or histogram, he or she usually asks two basic questions:

Section 11-2 discusses three possible answers to the first question. The book calls them measures of central tendency. They are

For mean and median there are two different formulas each: one for individual data points (ungrouped data), and one for grouped data. They are different, and you have to learn them both. The Excel functions can only handle ungrouped data. There are no built-in functions for grouped data, as far as I know.

You should check if your calculator has some built-in functions for computing mean and median. That will save you a lot of key punching, and cut down on the chance of making a mistake. Check whether your calculator can handle grouped data or not; mine can't.

Section 11-3 discusses two possible answers to the second question. The book calls them measures of dispersion. They are

As with mean and median, there are different formulas for ungrouped and grouped data. Again, Excel (and most likely your calculator) can only handle the ungrouped data.

Exam 4

The exam covers the topics from chapters 7 and 8. The questions can all be done by hand or with a calculator, but you are welcome to use Excel during the exam if you want. If you have a calculator that can do combinations and permutations, or at least the factorial, that will be helpful. A calculator is needed for the exam.

Specifically, the following topics will be on the exam:

You can skip the subsections related to odds and to empirical frequency.

Assignments

If you want to work ahead, you can also start on HW 11


Last Updated: Wednesday, August 5, 2015