[Dummies 01] • Statistics for Dummies by Rumsey, Deborah J. -- Read -- Imperial Library of Trantor

Index

Statistics for Dummies Introduction

About This Book Conventions Used in This Book Foolish Assumptions How This Book Is Organized

Part I: Vital Statistics about Statistics Part II: Number-Crunching Basics Part III: Determining the Odds Part IV: Wading through the Results Part V: Guesstimating with Confidence Part VI: Putting a Claim to the (Hypothesis) Test Part VII: Statistical Studies: The Inside Scoop Part VIII: The Part of Tens Appendix

Icons Used in This Book Where to Go from Here

Part I: Vital Statistics about Statistics

Chapter List

Chapter 1: The Statistics of Everyday Life

Statistics and the Media Blitz: More Questions than Answers?

Probing popcorn problems Venturing into viruses Comprehending crashes Mulling malpractice Belaboring the loss of land Scrutinizing schools Studying sports Banking on business news Taking in the travel news Talking sex (and statistics) with Dr. Ruth Whetting your appetite for weather Musing about movies Highlighting horoscopes

Using Statistics at Work

Delivering babies — and information Posing for pictures Poking through pizza data Working in the office of statistics

Chapter 2: Statistics Gone Wrong

Taking Control: So Many Numbers, So Little Time Detecting Errors, Exaggerations, and Just Plain Lies

Checking the math

Microwaving just doesn't add up Four out of five — really?

Uncovering misleading statistics

Crime statistics that don't pay Checking your sources Counting on the sample size Your doctor's time: Quantity or quality? Reporting beyond the scope

Looking for lies in all the right places

Feeling the Impact of Misleading Statistics

Chapter 3: Tools of the Trade

Statistics: More than Just Numbers Grabbing Some Basic Statistical Jargon

Population Sample Random Bias Data Data set Statistic Mean (average) Median Standard deviation Percentile Standard score Normal distribution (or bell-shaped curve) Experiments

Treatment group versus control group Placebo Blind and double-blind

Surveys (polls) Estimation

Margin of error Confidence interval

Probability versus odds The law of averages Hypothesis testing

P-value Statistically significant

Correlation and causation

Part II: Number-Crunching Basics

Chapter List

Chapter 4: Getting the Picture—Charts and Graphs

Getting Graphic with Statistics Getting a Piece of the Pie Chart

Tallying personal expenses Sizing up the lottery Slicing up your tax dollars Predicting population trends Evaluating a pie chart

Raising the Bar on Bar Graphs

Tracking transportation expenses Highlighting mothers in the workforce Playing with the Ohio lottery Evaluating a bar graph

Putting Statistics on the Table

Examining birth statistics

Looking at percents versus totals Putting percents into perspective Keeping an eye on the units

Evaluating a table

Keeping Pace with Time Charts

Analyzing wage trends Charting plural births Evaluating a time chart

Picturing Data with a Histogram

Analyzing mothers' ages Crawling with a baby Interpreting a histogram Evaluating a histogram

Chapter 5: Means, Medians, and More

Summing Up Data with Statistics Summarizing Categorical Data Summarizing Numerical Data

Getting centered

Averaging out NBA salaries Splitting salaries down the median Interpreting the center: Comparing means to medians

Accounting for variation

Knowing what standard deviation means Calculating the standard deviation Interpreting the standard deviation Understanding the properties of the standard deviation Lobbying for the standard deviation Being out of range

Determining where you stand: Percentiles

Understanding percentiles Calculating percentiles Interpreting percentiles

Part III: Determining the Odds

Chapter List

Chapter 6: What Are the Chances?—Understanding Probability

Taking a Chance with Probability Gaining the Edge: Probability Basics

Getting the rules down Rolling the dice Models and simulations

Interpreting Probability Avoiding Probability Misconceptions

Looking more likely Predicting long or short term Thinking 50-50 Interpreting rare events

Connecting Probability with Statistics

Estimating Predicting Deciding Checking quality

Chapter 7: Gambling to Win

Betting on the House: Why Casinos Stay in Business Knowing a Little Probability Helps a Lotto

Having a 50-50 chance Picking winning numbers Buying lottery tickets — less can be more Predicting a boy or a girl Trying to win at slots

Part IV: Wading through the Results

Chapter List

Chapter 8: Measures of Relative Standing

Straightening Out the Bell Curve

Characterizing the normal distribution Describing the shape and center Measuring the variability Looking for most of the values: The empirical rule

Converting to a Standard Score

Focusing on the standard deviation Calculating the standard score Properties of standard scores Comparing apples and oranges using standard scores

Sizing Up Results Using Percentiles

Chapter 9: Caution—Sample Results Vary!

Expecting Sample Results to Vary Measuring Variability in Sample Results

Standard errors Sampling distributions Using the empirical rule to interpret standard errors Specifics of the central limit theorem

Checking out the ACT math scores What proportion needs math help?

Examining Factors That Influence Variability in Sample Results

Sample size Population variability

Chapter 10: Leaving Room for a Margin of Error

Overview Exploring the Importance of That Plus or Minus Finding the Margin of Error: A General Formula

Measuring sample variability Calculating margin of error for a sample proportion Reporting results Calculating margin of error for a sample average Being sure you're right

Determining the Impact of Sample Size

How large is large enough? Sample size and margin of error Bigger isn't always (that much) better!

Limiting the Margin of Error

Part V: Guesstimating with Confidence

Chapter List

Chapter 11: The Business of Estimation—Interpreting and Evaluating Confidence Intervals

Realizing That Not All Estimates Are Created Equal Linking a Statistic to a Parameter Making Your Best Guesstimate Interpreting Results with Confidence Spotting Misleading Confidence Intervals

Chapter 12: Calculating Accurate Confidence Intervals

Calculating a Confidence Interval Choosing a Confidence Level Zooming In on Width Factoring In the Sample Size Counting On Population Variability

Chapter 13: Commonly Used Confidence Intervals—Formulas and Examples

Calculating the Confidence Interval for the Population Mean Determining the Confidence Interval for the Population Proportion Developing a Confidence Interval for the Difference of Two Means Coming Up with the Confidence Interval for the Difference of Two Proportions

Part VI: Putting a Claim to the (Hypothesis) Test

Chapter List

Chapter 14: Claims, Tests, and Conclusions

Overview Responding to Claims: Some Do's and Don'ts

Knowing your options Steering clear of anecdotes Digging deeper

Doing a Hypothesis Test

Defining what you're testing Setting up the hypotheses

What's the alternative? Knowing which hypothesis is which

Gathering the evidence: The sample Compiling the evidence: The statistics Standardizing the evidence: The test statistic

Weighing the Evidence and Making Decisions: P-Values

P-value basics Caution: Interpretations will vary!

Knowing That You Could Be Wrong: Errors in Testing

Making a false alarm: Type-1 errors Missing a detection: Type-2 errors Drawing conclusions about their conclusions

Walking through a Hypothesis Test: The Big Picture

Reviewing the general steps for a hypothesis test (one means/proportions, large samples) Dealing with other hypothesis tests Handling smaller samples: The t-distribution

Chapter 15: Commonly Used Hypothesis Tests—Formulas and Examples

Overview Testing One Population Mean Testing One Population Proportion Comparing Two (Separate) Population Averages Testing for an Average Difference (Paired Data) Comparing Two Population Proportions

Part VII: Statistical Studies—The Inside Scoop

Chapter List

Chapter 16: Polls, Polls, and More Polls

Recognizing the Impact of Polls

Getting to the source Surveying what's hot Impacting lives

Behind the Scenes: The Ins and Outs of Surveys

Planning and designing a survey

Stating the purpose of the survey Defining the target population Choosing the type of survey Designing the questions Timing the survey

Selecting the sample Carrying out a survey

Collecting the data Following up, following up, and following up

Interpreting results; detecting problems

Organizing and analyzing Drawing conclusions

Chapter 17: Experiments—Medical Breakthroughs or Misleading Results?

Determining What Sets Experiments Apart

Examining experiments Observing observational studies Respecting ethical issues

Designing a Good Experiment

Selecting the sample size

Understanding that small samples don't make for big conclusions Checking your definition of "sample size"

Choosing the subjects Randomly assigning subjects to groups

Realizing the importance of random assignment Controlling for the placebo effect

Controlling for confounding variables Double-blinding the experiment Collecting good data Analyzing the data properly Drawing appropriate conclusions

Overstating the results Taking the results one step beyond the actual data Generalizing results to people beyond the scope of the study

Making Informed Decisions about Experiments

Chapter 18: Looking for Links—Correlations and Associations

Overview Picturing the Relationship: Plots and Charts

Displaying bivariate numerical data

Making a scatterplot Interpreting a scatterplot

Displaying bivariate categorical data

Quantifying the Relationship: Correlations and Other Measures

Quantifying a relationship between two numerical variables

Calculating the correlation coefficient (r) Interpreting the correlation Understanding the properties of the correlation coefficient

Quantifying a relationship between two categorical variables

Explaining the Relationship: Association and Correlation versus Causation

Taking aspirin does seem to help Turning up the heat on cricket chirps

Making Predictions: Regression and Other Methods

Making predictions with correlated data

Getting a formula for best-fitting line Finding the slope of the best-fitting line Finding the y-intercept of the best-fitting line Finding the best-fitting line for cricket chirps and temperature Comparing the working model to the data subset Predicting temperature with cricket chirps

Making predictions with two associated categorical variables

Chapter 19: Statistics and Toothpaste—Quality Control

Full-Filling Expectations Squeezing Quality out of a Toothpaste Tube

Understanding that quality = accuracy + consistency Using control charts to monitor quality Defining accuracy Defining consistency Expecting a normal distribution Finding the control limits Monitoring the process

Part VIII: The Part of Tens

Chapter List

Chapter 20: Ten Criteria for a Good Survey

The Target Population Is Well Defined The Sample Matches the Target Population The Sample Is Randomly Selected The Sample Size Is Large Enough Good Follow-Up Minimizes Non-Response The Type of Survey Used Is Appropriate The Questions Are Well Worded The Survey Is Properly Timed The Survey Personnel Are Well Trained The Survey Answers the Original Question

Chapter 21: Ten Common Statistical Mistakes

Misleading Graphs

Pie charts Bar graphs Time charts Histograms

Biased Data No Margin of Error Non-Random Samples Missing Sample Sizes Misinterpreted Correlations Confounding Variables Botched Numbers Selectively Reporting Results The Almighty Anecdote

Sources

Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19

Index

Symbols

Index

List of Figures

Chapter 2: Statistics Gone Wrong Chapter 3: Tools of the Trade Chapter 4: Getting the Picture—Charts and Graphs Chapter 5: Means, Medians, and More Chapter 6: What Are the Chances?—Understanding Probability Chapter 7: Gambling to Win Chapter 8: Measures of Relative Standing Chapter 9: Caution—Sample Results Vary! Chapter 14: Claims, Tests, and Conclusions Chapter 18: Looking for Links—Correlations and Associations Chapter 19: Statistics and Toothpaste—Quality Control Chapter 21: Ten Common Statistical Mistakes

List of Tables

Chapter 2: Statistics Gone Wrong Chapter 4: Getting the Picture—Charts and Graphs Chapter 5: Means, Medians, and More Chapter 6: What Are the Chances?—Understanding Probability Chapter 8: Measures of Relative Standing Chapter 9: Caution—Sample Results Vary! Chapter 10: Leaving Room for a Margin of Error Chapter 14: Claims, Tests, and Conclusions Chapter 15: Commonly Used Hypothesis Tests—Formulas and Examples Chapter 16: Polls, Polls, and More Polls Chapter 18: Looking for Links—Correlations and Associations

List of Sidebars

Chapter 1: The Statistics of Everyday Life Chapter 2: Statistics Gone Wrong Chapter 12: Calculating Accurate Confidence Intervals Chapter 16: Polls, Polls, and More Polls Chapter 17: Experiments—Medical Breakthroughs or Misleading Results?

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