Statistics Workbook For Dummies

by Rumsey, Deborah J.

• ISBN13: 9780764584664
• ISBN10: 0764584669
• Format: Paperback
• Copyright: 2005-05-27
• Publisher: For Dummies

Summary

A friendly, hands-on guide to the dreaded field of statistics Competence in and understanding statistics is important to success in such fields as business and science, and is often a requirement for college students in a variety of programs. This handy guide complements author Deborah Rumsey's Statistics For Dummies by presenting exercises and fully worked solutions that let students and professionals practice and sharpen their statistical skills and understanding of the subject. Offering a simple, straightforward examination of the process and products of statistical computation-as well as a wealth of tips and tricks-Statistics Workbook For Dummies is an invaluable resource for reinforcing the concepts and practice of statistics.

Author Biography

Deborah Rumsey has a PhD in Statistics from The Ohio State University (1993). Upon graduating, she joined the faculty in the Department of Statistics at Kansas State University, winning the distinguished Presidential Teaching Award and earning tenure and promotion in 1998. In 2000, she returned to Ohio State and is now a Statistics Education Specialist/Auxiliary Faculty Member for the Department of Statistics. Dr. Rumsey has served on the American Statistical Association’s Statistics Education Executive Committee and as the Editor of the Teaching Bits Section of the Journal of Statistics Education. She’s the author of the book Statistics For Dummies (Wiley), and she has published many papers and given many professional presentations on the subject of statistics education. Her particular research interests are curriculum materials development, teacher training and support, and immersive learning environments. Her passions, besides teaching, include her family, fishing, bird watching, driving a John Deere tractor, and Ohio State Buckeye football (not necessarily in that order).

Table of Contents

Introduction	1	(1)
About This Book	1	(1)
Conventions Used in This Book	2	(1)
Foolish Assumptions	2	(1)
How This Book Is Organized	3	(1)
Part I: Getting Off to a Statistically Significant Start	3	(1)
Part II: Probability, the Normal Distribution, and the Central Limit Theorem (Are You Having Fun Yet?)	3	(1)
Part III: Guesstimating with Confidence	3	(1)
Part IV: Putting a Claim to the (Hypothesis) Test	3	(1)
Part V: Getting the Inside Scoop on Statistical Studies	3	(1)
Part VI: Exploring and Describing Relationships between Two Variables	4	(1)
Part VII: The Part of Tens	4	(1)
Icons Used in This Book	4	(1)
Where to Go from Here	5	(2)
Part I: Getting Off to a Statistically Significant Start	7	(62)
Summarizing Categorical Data: Counts and Percents	9	(10)
Counting On the Frequency	9	(2)
Relating with Percentages	11	(2)
Interpreting Counts and Percents with Caution	13	(2)
Answers to Problems in Summarizing Categorical Data	15	(4)
Organizing Categorical Data: Charts and Graphs	19	(16)
Making, Interpreting, and Evaluating Pie Charts	19	(6)
Making, Interpreting, and Evaluating Bar Graphs	25	(4)
Answers to Problems in Organizing Categorical Data	29	(6)
Organizing Quantitative Data: Charts and Graphs	35	(18)
Creating a Histogram	35	(3)
Making Sense of Histograms	38	(5)
Spotting a Misleading Histogram	43	(2)
Looking at Line Graphs	45	(3)
Answers to Problems in Organizing Quantitative Data	48	(5)
Summarizing Quantitative Data: Means, Medians, and More	53	(16)
Using Histograms to Explore the Shape of Data	53	(2)
Finding and Interpreting Measures of Center	55	(2)
Finding and Interpreting Measures of Spread	57	(2)
Straightening Out Skewed Data	59	(2)
Understanding the Empirical Rule (a.k.a. the 68-95-99.7 Percent Rule)	61	(3)
Answers to Problems in Summarizing Quantitative Data	64	(5)
Part II: Probability, the Normal Distribution, and the Central Limit Theorem (Are You Having Fun Yet?)	69	(46)
Understanding Probability Basics	71	(8)
Grasping the Rules of Probability	71	(2)
Avoiding Probability Misconceptions	73	(2)
Making Predictions Using Probability	75	(2)
Answers to Problems in Probability	77	(2)
Measures of Relative Standing and the Normal Distribution	79	(22)
Mastering the Normal Distribution	79	(3)
Converting to the Standard Normal Distribution: Finding and Interpreting Standard (Z) Scores	82	(3)
Knowing Where You Stand with Percentiles	85	(2)
Finding Probabilities for a Normal Distribution	87	(3)
Determining the Original Score When Given the Percentile (Backwards Normal)	90	(3)
Answers to Problems in Normal Distribution	93	(8)
Demystifying Sampling Distributions and the Central Limit Theorem	101	(14)
Exactly What Is a Sampling Distribution?	101	(3)
Clearing Up the Central Limit Theorem (Once and for All)	104	(2)
Finding Probabilities for Means and Proportions with the Central Limit Theorem	106	(2)
When Your Sample's Too Small for the Central Limit Theorem: Employing the T-Distribution	108	(3)
Answers to Problems in Sampling Distributions and the Central Limit Theorem	111	(4)
Part III: Guesstimating with Confidence	115	(38)
Making Sense of Margin of Error	117	(12)
Reviewing Margin of Error	117	(2)
Calculating the Margin of Error for Means and Proportions	119	(3)
Increasing and Decreasing Margin of Error	122	(1)
Interpreting Margin of Error Correctly	123	(3)
Answers to Problems in Making Sense of Margin of Error	126	(3)
Calculating Confidence Intervals	129	(16)
Walking through a Confidence Interval: An Overview with Points to Watch For	129	(3)
Deriving a Confidence Interval for a Population Mean	132	(2)
Figuring a Confidence Interval for a Population Proportion	134	(2)
Calculating a Confidence Interval for the Difference of Two Means	136	(2)
Computing a Confidence Interval for the Difference of Two Proportions	138	(2)
Answers to Problems in Calculating Confidence Intervals	140	(5)
Deciphering Your Confidence Interval	145	(8)
Interpreting Confidence Intervals the Right Way: How to Satisfy Your Instructor	145	(4)
Evaluating Confidence Interval Results: What the Formulas Don't Tell You	149	(2)
Answers to Problems in Confidence Intervals	151	(2)
Part IV: Putting a Claim to the (Hypothesis) Test	153	(36)
Testing Hypotheses	155	(20)
Walking Through a Hypothesis Test	155	(4)
Testing a Hypothesis about a Population Mean	159	(2)
Testing a Hypothesis about a Population Proportion	161	(2)
Testing for a Difference between Two Population Means	163	(2)
Testing for a Mean Difference (Paired T-Test)	165	(2)
Testing a Hypothesis about Two Population Proportions	167	(2)
Answers to Problems in Testing Hypotheses	169	(6)
Taking the Guesswork Out of p-Values and Type I and II Errors	175	(14)
Understanding What p-Values Measure	175	(2)
Test (Statistic) Time: Figuring Out p-Values	177	(2)
The Value Breakdown: Interpreting p-Values Properly	179	(3)
Deciphering Type I Errors	182	(1)
Deciphering and Distinguishing Type II Errors	183	(3)
Answers to Problems in p-Values and Type I and II Errors	186	(3)
Part V: Getting the Inside Scoop on Statistical Studies	189	(22)
Examining Polls and Surveys	191	(10)
Planning and Designing a Survey	191	(2)
Selecting a Random Sample	193	(2)
Carrying Out a Survey Properly	195	(1)
Interpreting and Evaluating Survey Results	196	(3)
Answers to Problems in Polls and Surveys	199	(2)
Evaluating Experiments	201	(10)
Distinguishing Experiments from Observational Studies	201	(2)
Designing a Good Experiment	203	(3)
Looking for Cause and Effect: Interpreting Experiment Results	206	(2)
Answers to Problems in Evaluating Experiments	208	(3)
Part VI: Exploring and Describing Relationships between Two Variables	211	(40)
Looking for Links in Categorical Data: Two-Way Tables	213	(22)
Understanding Two-Way Tables Inside and Out	213	(3)
Working with Intersection, Unions, and the Addition Rule	216	(2)
Figuring Marginal Probabilities	218	(2)
Nailing Down Conditional Probabilities and the Multiplication Rule	220	(4)
Inspecting the Independence of Categorical Variables	224	(4)
Answers to Problems in Two-Way Tables	228	(7)
Searching for Links in Quantitative Data: Correlation and Regression	235	(16)
Relating X and Y with a Scatterplot	235	(2)
Toeing the Line of Correlation	237	(3)
Picking Out the Best Fitting Regression Line	240	(2)
Interpreting the Regression Line and Making Predictions	242	(2)
Checking the Fit of the Regression Line	244	(3)
Answers to Problems in Correlation and Regression	247	(4)
Part VII: The Part of Tens	251	(28)
Math Review: Ten Steps to a Better Grade	253	(10)
Know Your Math Symbols	253	(1)
Uproot Roots and Powers	254	(1)
Treat Fractions with Extra Care	254	(1)
Obey the Order of Operations	255	(1)
Avoid Rounding Errors	256	(1)
Get Comfortable with Formulas	256	(1)
Stay Calm when Formulas Get Tough	257	(1)
Feel Fine about Functions	258	(1)
Know When Your Answer Is Wrong	259	(1)
Show Your Work	260	(3)
Top Ten Statistical Formulas	263	(10)
Mean (or Average)	263	(1)
Median	264	(1)
Sample Standard Deviation	264	(2)
Correlation	266	(1)
Margin of Error for the Sample Mean	266	(1)
Sample Size Needed for X	267	(1)
Test Statistic for the Mean	268	(1)
Margin of Error for the Sample Proportion	269	(1)
Sample Size Needed for p	270	(1)
Test Statistic for the Proportion	271	(2)
Ten Ways to Spot Common Statistical Mistakes	273	(6)
Scrutinizing Graphs	273	(1)
Searching for and Specifying Bias	274	(1)
Marking the Margin of Error	275	(1)
Scanning for Sample Size	275	(1)
Studying Sample Selection (Gotta Be Random)	276	(1)
Checking for Confounding Variables	276	(1)
Considering Correlation	277	(1)
Doing the Math	277	(1)
Detecting Selective Reporting	278	(1)
Avoiding the Anecdote	278	(1)
Index	279