Statistics Workbook For Dummies with Online Practice

Deborah J. Rumsey

• Publisher: For Dummies
• Year: 2019
• ISBN:
  9781119547686
• Edition: 2
• Topic: Mathematics
• Subtopic: Probability & Statistics
• Index: Mathematics

Practice your way to a higher statistics score

The adage that "practice makes perfect" is never truer than with math problems. S tatistics Workbook For Dummies with Online Practice provides succinct content reviews for every topic, with plenty of examples and practice problems for each concept, in the book and online.

Every lesson begins with a concept review, followed by a few example problems and plenty of practice problems. There's a step-by-step solution for every problem, with tips and tricks to help with comprehension and retention. New for this edition, free online practice quizzes for each chapter provide extra opportunities to test your knowledge and understanding.

• Get FREE access to chapter quizzes in an online test bank
• Work along with each chapter or use the test bank for final exam review
• Discover which statistical measures are most meaningful

Scoring high in your Statistics class has never been easier!

Part 1

Getting Off to a Statistically Significant Start

IN THIS PART …

Get down to the basics of number crunching.

Make and interpret charts and graphs.

Crank out and understand descriptive statistics.

Develop important skills for critiquing others’ statistics.

Chapter 1

Summarizing Categorical Data: Counts and Percents

IN THIS CHAPTER

Making tables to summarize categorical data

Highlighting the difference between frequencies and relative frequencies

Interpreting and evaluating tables

Categorical data is data in which individuals are placed into groups or categories — for example gender, region, or type of movie. Summarizing categorical data involves boiling down all the information into just a few numbers that tell its basic story. Because categorical data involves pieces of data that belong in categories, you have to look at how many individuals fall into each group and summarize the numbers appropriately. In this chapter, you practice making, interpreting, and evaluating frequency and relative frequency tables for categorical data.

Counting On the Frequency

One way to summarize categorical data is to simply count, or tally up, the number of individuals that fall into each category. The number of individuals in any given category is called the frequency (or count) for that category. If you list all the possible categories along with the frequency for each, you create a frequency table. The total of all the frequencies should equal the size of the sample (because you place each individual in one category).

See the following for an example of summarizing data by using a frequency table.

Q. Suppose that you take a sample of 10 people and ask them all whether they own a cellphone. Each person falls into one of two categories: yes or no. The data are shown in the following table.

Person #	Cellphone	Person #	Cellphone
1	Y	6	Y
2	N	7	Y
3	Y	8	Y
4	N	9	N
5	Y	10	Y

1. Summarize this data in a frequency table.
2. What’s an advantage of summarizing categorical data?

A. Data summaries boil down the data quickly and clearly.

1. The frequency table for this data is shown in the following table.
2. A data summary allows you to see patterns in the data, which aren’t clear if you look only at the original data.

Own a Cellphone?	Frequency
Y	7
N	3
Total	10

1 You survey 20 shoppers to see what type of soft drink they like best, Brand A or Brand B. The results are: A, A, B, B, B, B, B, B, A, A, A, B, A, A, A, A, B, B, A, A. Which brand do the shoppers prefer? Make a frequency table and explain your answer.

2 A local city government asks voters to vote on a tax levy for the local school district. A total of 18,726 citizens vote on the issue. The yes count comes in at 10,479, and the rest of the voters said no.

1. Show the results in a frequency table.
2. Why is it important to include the total number at the bottom of a frequency table?

3 A zoo asks 1,000 people whether they’ve been to the zoo in the last year. The surveyors count that 592 say yes, 198 say no, and 210 don’t respond.

1. Show the results in a frequency table.
2. Explain why you need to include the people who don’t respond.

4 Suppose that instead of showing the number in each group, you show just the percentage (called a relative frequency). What’s one advantage a relative frequency table has over a frequency table?

Relating with Percentages

Another way to summarize categorical data is to show the percentage of individuals who fall into each category, thereby creating a relative frequency. The relative frequency of a given category is the frequency (number of individuals in that category) divided by the total sample size, multiplied by 100 to get the percentage. For example, if you survey 50 people and 10 are in favor of a certain issue, the relative frequency of the “in-fa...

Table of contents

• Cover
• Table of Contents
• Introduction
• Part 1: Getting Off to a Statistically Significant Start
• Part 2: Probability, Distributions, and the Central Limit Theorem (Are You Having Fun Yet?)
• Part 3: Guesstimating and Hypothesizing with Confidence
• Part 4: Statistical Studies and the Hunt for a Meaningful Relationship
• Part 5: The Part of Tens
• Appendix: Tables for Reference
• Index
• About the Author
• Advertisement Page
• Connect with Dummies
• End User License Agreement