a. To determine whether a new sleeping pill has an effect that varies with dosage, a researcher rand

  

a. To determine whether a new sleeping pill has an effect that varies with dosage, a researcher randomly assigns adult insomniacs, in equal numbers, to receive either 4 or 8 grams of the sleeping pill. The amount of sleeping time is measured for each subject during an 8-hour period after the administration of the dosage. What type of design is this, and what type of statistic is needed to analyze the data?b. Dr. Bill Board designs a 2 X 2 between-subjects factorial design, where Factor A is word frequency (low or high) and Factor B is category cues (no cues or cues). Assume that the data are interval. What type of statistic is needed to analyze the data?
_statistics_11th_edition_by_robert_s_witte.pdf

Unformatted Attachment Preview

Don't use plagiarized sources. Get Your Custom Essay on
a. To determine whether a new sleeping pill has an effect that varies with dosage, a researcher rand
Just from $13/Page
Order Essay

Witte11e_fm.indd 16
11/18/2016 8:18:14 PM
STATISTICS
Eleventh Edition
Robert S. Witte
Emeritus, San Jose State University
John S. Witte
University of California, San Francisco
Witte11e_fm.indd 1
11/18/2016 8:18:13 PM
VP AND EDITORIAL DIRECTOR
EDITORIAL DIRECTOR
EDITORIAL ASSISTANT
EDITORIAL MANAGER
CONTENT MANAGEMENT DIRECTOR
CONTENT MANAGER
SENIOR CONTENT SPECIALIST
PRODUCTION EDITOR
COVER PHOTO CREDIT
George Hoffman
Veronica Visentin
Ethan Lipson
Gladys Soto
Lisa Wojcik
Nichole Urban
Nicole Repasky
Abidha Sulaiman
M.C. Escher’s Spirals © The M.C. Escher Company
– The Netherlands
This book was set in 10/11 Times LT Std by SPi Global and printed and bound by Lightning Source Inc. The
cover was printed by Lightning Source Inc.
Founded in 1807, John Wiley & Sons, Inc. has been a valued source of knowledge and understanding for
more than 200 years, helping people around the world meet their needs and fulfill their aspirations. Our
company is built on a foundation of principles that include responsibility to the communities we serve and
where we live and work. In 2008, we launched a Corporate Citizenship Initiative, a global effort to address
the environmental, social, economic, and ethical challenges we face in our business. Among the issues we are
addressing are carbon impact, paper specifications and procurement, ethical conduct within our business and
among our vendors, and community and charitable support. For more information, please visit our website:
www.wiley.com/go/citizenship.
Copyright © 2017, 2010, 2007 John Wiley & Sons, Inc. All rights reserved.
No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by
any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission
of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923 (Web site: www.copyright.com). Requests to
the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc.,
111 River Street, Hoboken, NJ 07030-5774, (201) 748-6011, fax (201) 748-6008, or online at: www.wiley.
com/go/permissions.
Evaluation copies are provided to qualified academics and professionals for review purposes only, for use
in their courses during the next academic year. These copies are licensed and may not be sold or transferred
to a third party. Upon completion of the review period, please return the evaluation copy to Wiley. Return
instructions and a free of charge return shipping label are available at: www.wiley.com/go/returnlabel. If you
have chosen to adopt this textbook for use in your course, please accept this book as your complimentary
desk copy. Outside of the United States, please contact your local sales representative.
ISBN: 978-1-119-25451-5(PBK)
ISBN: 978-1-119-25445-4(EVALC)
Library of Congress Cataloging-in-Publication Data
Names: Witte, Robert S. | Witte, John S.
Title: Statistics / Robert S. Witte, Emeritus, San Jose State University,
John S. Witte, University of California, San Francisco.
Description: Eleventh edition. | Hoboken, NJ: John Wiley & Sons, Inc.,
[2017] | Includes index.
Identifiers: LCCN 2016036766 (print) | LCCN 2016038418 (ebook) | ISBN
9781119254515 (pbk.) | ISBN 9781119299165 (epub)
Subjects: LCSH: Statistics.
Classification: LCC QA276.12 .W57 2017 (print) | LCC QA276.12 (ebook) | DDC
519.5—dc23
LC record available at https://lccn.loc.gov/2016036766
The inside back cover will contain printing identification and country of origin if omitted from this page.
In addition, if the ISBN on the back cover differs from the ISBN on this page, the one on the back cover
is correct.
Witte11e_fm.indd 2
11/18/2016 8:18:13 PM
To Doris
Witte11e_fm.indd 3
11/18/2016 8:18:13 PM
Preface
TO THE READER
Students often approach statistics with great apprehension. For many, it is a required
course to be taken only under the most favorable circumstances, such as during a quarter or semester when carrying a light course load; for others, it is as distasteful as a visit
to a credit counselor—to be postponed as long as possible, with the vague hope that
mounting debts might miraculously disappear. Much of this apprehension doubtless
rests on the widespread fear of mathematics and mathematically related areas.
This book is written to help you overcome any fear about statistics. Unnecessary
quantitative considerations have been eliminated. When not obscured by mathematical
treatments better reserved for more advanced books, some of the beauty of statistics, as
well as its everyday usefulness, becomes more apparent.
You could go through life quite successfully without ever learning statistics. Having
learned some statistics, however, you will be less likely to flinch and change the topic
when numbers enter a discussion; you will be more skeptical of conclusions based on
loose or erroneous interpretations of sets of numbers; you might even be more inclined
to initiate a statistical analysis of some problem within your special area of interest.
TO THE INSTRUCTOR
Largely because they panic at the prospect of any math beyond long division, many
students view the introductory statistics class as cruel and unjust punishment. A halfdozen years of experimentation, first with assorted handouts and then with an extensive
set of lecture notes distributed as a second text, convinced us that a book could be written for these students. Representing the culmination of this effort, the present book
provides a simple overview of descriptive and inferential statistics for mathematically
unsophisticated students in the behavioral sciences, social sciences, health sciences,
and education.
PEDAGOGICAL FEATURES
• Basic concepts and procedures are explained in plain English, and a special effort
has been made to clarify such perennially mystifying topics as the standard deviation, normal curve applications, hypothesis tests, degrees of freedom, and analysis of variance. For example, the standard deviation is more than a formula; it
roughly reflects the average amount by which individual observations deviate
from their mean.
• Unnecessary math, computational busy work, and subtle technical distinctions
are avoided without sacrificing either accuracy or realism. Small batches of data
define most computational tasks. Single examples permeate entire chapters or
even several related chapters, serving as handy frames of reference for new concepts and procedures.
iv
Witte11e_fm.indd 4
11/18/2016 8:18:13 PM
P R E FA C E
v
• Each chapter begins with a preview and ends with a summary, lists of important
terms and key equations, and review questions.
• Key statements appear in bold type, and step-by-step summaries of important
procedures, such as solving normal curve problems, appear in boxes.
• Important definitions and reminders about key points appear in page margins.
• Scattered throughout the book are examples of computer outputs for three of the
most prevalent programs: Minitab, SPSS, and SAS. These outputs can be either
ignored or expanded without disrupting the continuity of the text.
• Questions are introduced within chapters, often section by section, as Progress
Checks. They are designed to minimize the cumulative confusion reported by
many students for some chapters and by some students for most chapters. Each
chapter ends with Review Questions.
• Questions have been selected to appeal to student interests: for example, probability calculations, based on design flaws, that re-create the chillingly high likelihood of the Challenger shuttle catastrophe (8.18, page 165); a t test analysis of
global temperatures to evaluate a possible greenhouse effect (13.7, page 244);
and a chi-square test of the survival rates of cabin and steerage passengers aboard
the Titanic (19.14, page 384).
• Appendix B supplies answers to questions marked with asterisks. Other appendices provide a practical math review complete with self-diagnostic tests, a glossary of important terms, and tables for important statistical distributions.
INSTRUCTIONAL AIDS
An electronic version of an instructor’s manual accompanies the text. The instructor’s
manual supplies answers omitted in the text (for about one-third of all questions), as well
as sets of multiple-choice test items for each chapter, and a chapter-by-chapter commentary
that reflects the authors’ teaching experiences with this material. Instructors can access
this material in the Instructor Companion Site at http://www.wiley.com/college/witte.
An electronic version of a student workbook, prepared by Beverly Dretzke of the
University of Minnesota, also accompanies the text. Self-paced and self-correcting, the
workbook contains problems, discussions, exercises, and tests that supplement the text.
Students can access this material in the Student Companion Site at http://www.wiley.
com/college/witte.
CHANGES IN THIS EDITION
• Update discussion of polling and random digit dialing in Section 8.4
• A new Section 14.11 on the “file drawer effect,” whereby nonsignificant statistical findings are never published and the importance of replication.
• Updated numerical examples.
• New examples and questions throughout the book.
• Computer outputs and website have been updated.
Witte11e_fm.indd 5
11/18/2016 8:18:13 PM
vi
P R E FA C E
USING THE BOOK
The book contains more material than is covered in most one-quarter or one-semester
courses. Various chapters can be omitted without interrupting the main development.
Typically, during a one-semester course we cover the entire book except for analysis of
variance (Chapters 16, 17, and 18) and tests of ranked data (Chapter 20). An instructor
who wishes to emphasize inferential statistics could skim some of the earlier chapters,
particularly Normal Distributions and Standard Scores (z) (Chapter 5), and Regression
(Chapter 7), while an instructor who desires a more applied emphasis could omit Populations, Samples, and Probability (Chapter 8) and More about Hypothesis Testing
(Chapter 11).
ACKNOWLEDGMENTS
The authors wish to acknowledge their immediate family: Doris, Steve, Faith, Mike,
Sharon, Andrea, Phil, Katie, Keegan, Camy, Brittany, Brent, Kristen, Scott, Joe, John,
Jack, Carson, Sam, Margaret, Gretchen, Carrigan, Kedrick, and Alika. The first author
also wishes to acknowledge his brothers and sisters: Henry, the late Lila, J. Stuart, A.
Gerhart, and Etz; deceased parents: Henry and Emma; and all friends and relatives,
past and present, including Arthur, Betty, Bob, Cal, David, Dick, Ellen, George, Grace,
Harold, Helen, John, Joyce, Kayo, Kit, Mary, Paul, Ralph, Ruth, Shirley, and Suzanne.
Numerous helpful comments were made by those who reviewed the current and
previous editions of this book: John W. Collins, Jr., Seton Hall University; Jelani Mandara, Northwestern University; L. E. Banderet, Northeastern University; S. Natasha
Beretvas, University of Texas at Austin; Patricia M. Berretty, Fordham University;
David Coursey, Florida State University; Shelia Kennison, Oklahoma State University; Melanie Kercher, Sam Houston State University; Jennifer H. Nolan, Loyola
Marymount University; and Jonathan C. Pettibone, University of Alabama in Huntsville; Kevin Sumrall, Montgomery College; Sky Chafin, Grossmont College; Christine
Ferri, Richard Stockton College of NJ; Ann Barich, Lewis University.
Special thanks to Carson Witte who proofread the entire manuscript twice.
Excellent editorial support was supplied by the people at John Wiley & Sons, Inc.,
most notably Abidha Sulaiman and Gladys Soto.
Witte11e_fm.indd 6
11/18/2016 8:18:13 PM
Contents
PREFACE
iv
ACKNOWLEDGMENTS
1
INTRODUCTION
vi
1
1.1
WHY STUDY STATISTICS? 2
1.2
WHAT IS STATISTICS? 2
1.3
MORE ABOUT INFERENTIAL STATISTICS
1.4
THREE TYPES OF DATA 6
1.5
LEVELS OF MEASUREMENT 7
1.6
TYPES OF VARIABLES 11
1.7
HOW TO USE THIS BOOK 15
Summary 16
Important Terms 17
Review Questions 17
3
PART 1 Descriptive Statistics: Organizing
and Summarizing Data 21
2
DESCRIBING DATA WITH TABLES AND GRAPHS
TABLES (FREQUENCY DISTRIBUTIONS)
2.1
2.2
2.3
2.4
2.5
2.6
2.7
22
23
FREQUENCY DISTRIBUTIONS FOR QUANTITATIVE DATA 23
GUIDELINES 24
OUTLIERS 27
RELATIVE FREQUENCY DISTRIBUTIONS 28
CUMULATIVE FREQUENCY DISTRIBUTIONS 30
FREQUENCY DISTRIBUTIONS FOR QUALITATIVE (NOMINAL) DATA
INTERPRETING DISTRIBUTIONS CONSTRUCTED BY OTHERS 32
GRAPHS
31
33
2.8
GRAPHS FOR QUANTITATIVE DATA 33
2.9
TYPICAL SHAPES 37
2.10 A GRAPH FOR QUALITATIVE (NOMINAL) DATA
2.11 MISLEADING GRAPHS 40
2.12 DOING IT YOURSELF 41
Summary 42
Important Terms 43
Review Questions 43
39
vii
Witte11e_fm.indd 7
11/18/2016 8:18:13 PM
viii
CONTENTS
3
DESCRIBING DATA WITH AVERAGES
47
3.1
MODE 48
3.2
MEDIAN 49
3.3
MEAN 51
3.4
WHICH AVERAGE? 53
3.5
AVERAGES FOR QUALITATIVE AND RANKED DATA
Summary 56
Important Terms 57
Key Equation 57
Review Questions 57
4
DESCRIBING VARIABILITY
55
60
4.1
INTUITIVE APPROACH 61
4.2
RANGE 62
4.3
VARIANCE 63
4.4
STANDARD DEVIATION 64
4.5
DETAILS: STANDARD DEVIATION 67
4.6
DEGREES OF FREEDOM (df ) 75
4.7
INTERQUARTILE RANGE (IQR) 76
4.8
MEASURES OF VARIABILITY FOR QUALITATIVE AND RANKED DATA
Summary 78
Important Terms 79
Key Equations 79
Review Questions 79
5
NORMAL DISTRIBUTIONS AND STANDARD (z) SCORES
5.1
THE NORMAL CURVE 83
5.2
z SCORES 86
5.3
STANDARD NORMAL CURVE 87
5.4
SOLVING NORMAL CURVE PROBLEMS
5.5
FINDING PROPORTIONS 90
5.6
FINDING SCORES 95
5.7
MORE ABOUT z SCORES 100
Summary 103
Important Terms 103
Key Equations 103
Review Questions 103
6
Witte11e_fm.indd 8
82
89
DESCRIBING RELATIONSHIPS: CORRELATION
6.1
6.2
6.3
6.4
6.5
6.6
78
107
AN INTUITIVE APPROACH 108
SCATTERPLOTS 109
A CORRELATION COEFFICIENT FOR QUANTITATIVE DATA: r
DETAILS: COMPUTATION FORMULA FOR r 117
OUTLIERS AGAIN 118
OTHER TYPES OF CORRELATION COEFFICIENTS 119
113
11/18/2016 8:18:13 PM
CONTENTS
ix
6.7
COMPUTER OUTPUT 120
Summary 123
Important Terms and Symbols 124
Key Equations 124
Review Questions 124
7
REGRESSION
126
7.1
TWO ROUGH PREDICTIONS 127
7.2
A REGRESSION LINE 128
7.3
LEAST SQUARES REGRESSION LINE 130
7.4
STANDARD ERROR OF ESTIMATE, sy |x 133
7.5
ASSUMPTIONS 135
7.6
INTERPRETATION OF r 2 136
7.7
MULTIPLE REGRESSION EQUATIONS 141
7.8
REGRESSION TOWARD THE MEAN 141
Summary 143
Important Terms 144
Key Equations 144
Review Questions 144
PART 2 Inferential Statistics: Generalizing
Beyond Data 147
8
POPULATIONS, SAMPLES, AND PROBABILITY
POPULATIONS AND SAMPLES
8.1
8.2
8.3
8.4
8.5
8.6
149
POPULATIONS 149
SAMPLES 150
RANDOM SAMPLING 151
TABLES OF RANDOM NUMBERS 151
RANDOM ASSIGNMENT OF SUBJECTS
SURVEYS OR EXPERIMENTS? 154
PROBABILITY
153
155
8.7
DEFINITION 155
8.8
ADDITION RULE 156
8.9
MULTIPLICATION RULE 157
8.10 PROBABILITY AND STATISTICS
Summary 162
Important Terms 163
Key Equations 163
Review Questions 163
Witte11e_fm.indd 9
148
161
11/18/2016 8:18:13 PM
x
CONTENTS
9
SAMPLING DISTRIBUTION OF THE MEAN
168
9.1
WHAT IS A SAMPLING DISTRIBUTION? 169
9.2
CREATING A SAMPLING DISTRIBUTION FROM SCRATCH
9.3
SOME IMPORTANT SYMBOLS 173
9.4
MEAN OF ALL SAMPLE MEANS (μ ) 173
X
9.5
STANDARD ERROR OF THE MEAN (σ ) 174
X
9.6
SHAPE OF THE SAMPLING DISTRIBUTION 176
9.7
OTHER SAMPLING DISTRIBUTIONS 178
Summary 178
Important Terms 179
Key Equations 179
Review Questions 179
10
INTRODUCTION TO HYPOTHESIS TESTING: THE z TEST
170
182
10.1 TESTING A HYPOTHESIS ABOUT SAT SCORES 183
10.2 z TEST FOR A POPULATION MEAN 185
10.3 STEP-BY-STEP PROCEDURE 186
10.4 STATEMENT OF THE RESEARCH PROBLEM 187
10.5 NULL HYPOTHESIS (H0) 188
10.6 ALTERNATIVE HYPOTHESIS (H1) 188
10.7 DECISION RULE 189
10.8 CALCULATIONS 190
10.9 DECISION 190
10.10 INTERPRETATION 191
Summary 191
Important Terms 192
Key Equations 192
Review Questions 193
11
MORE ABOUT HYPOTHESIS TESTING
195
11.1 WHY HYPOTHESIS TESTS? 196
11.2 STRONG OR WEAK DECISIONS 197
11.3 ONE-TAILED AND TWO-TAILED TESTS 199
11.4 CHOOSING A LEVEL OF SIGNIFICANCE ( ) 202
11.5 TESTING A HYPOTHESIS ABOUT VITAMIN C 203
11.6 FOUR POSSIBLE OUTCOMES 204
11.7 IF H0 REALLY IS TRUE 206
11.8 IF H0 REALLY IS FALSE BECAUSE OF A LARGE EFFECT 207
11.9 IF H0 REALLY IS FALSE BECAUSE OF A SMALL EFFECT 209
11.10 INFLUENCE OF SAMPLE SIZE 211
11.11 POWER AND SAMPLE SIZE 213
Summary 216
Important Terms 217
Review Questions 218
Witte11e_fm.indd 10
11/18/2016 8:18:13 PM
CONTENTS
12
xi
ESTIMATION (CONFIDENCE INTERVALS)
221
12.1 POINT ESTIMATE FOR μ 222
12.2 CONFIDENCE INTERVAL (CI) FOR μ 222
12.3 INTERPRETATION OF A CONFIDENCE INTERVAL 226
12.4 LEVEL OF CONFIDENCE 226
12.5 EFFECT OF SAMPLE SIZE 227
12.6 HYPOTHESIS TESTS OR CONFIDENCE INTERVALS? 228
12.7 CONFIDENCE INTERVAL FOR POPULATION PERCENT 228
Summary 230
Important Terms 230
Key Equation 230
Review Questions 231
13
t TEST FOR ONE SAMPLE
233
13.1 GAS MILEAGE INVESTIGATION 234
13.2 SAMPLING DISTRIBUTION OF t 234
13.3 t TEST 237
13.4 COMMON THEME OF HYPOTHESIS TESTS 238
13.5 REMINDER ABOUT DEGREES OF FREEDOM 238
13.6 DETAILS: ESTIMATING THE STANDARD ERROR (s X )
13.7 DETAILS: CALCULATIONS FOR THE t TEST 239
13.8 CONFIDENCE INTERVALS FOR BASED ON t 241
13.9 ASSUMPTIONS 242
Summary 242
Important Terms 243
Key Equations 243
Review Questions 243
14
t TEST FOR TWO INDEPENDENT SAMPLES
238
245
14.1
14.2
14.3
14.4
14.5
14.6
14.7
14.8
EPO EXPERIMENT 246
STATISTICAL HYPOTHESES 247
SAMPLING DISTRIBUTION OF X1 – X 2 248
t TEST 250
DETAILS: CALCULATIONS FOR THE t TEST 252
p-VALUES 255
STATISTICALLY SIGNIFICANT RESULTS 258
ESTIMATING EFFECT SIZE: POINT ESTIMATES AND CONFIDENCE
INTERVALS 259
14.9 ESTIMATING EFFECT SIZE: COHEN’S d 262
14.10 META-ANALYSIS 264
14.11 IMPORTANCE OF REPLICATION 264
14.12 REPORTS IN THE LITERATURE 265
Witte11e_fm.indd 11
11/18/2016 8:18:13 PM
xii
CONTENTS
14.13 ASSUMPTIONS 266
14.14 COMPUTER OUTPUT 267
Summary 268
Important Terms 268
Key Equations 269
Review Questions 269
15
t TEST FOR TWO RELATED SAMPLES (REPEATED MEASURES)
15.1 EPO EXPERIMENT WITH REPEATED MEASURES 274
15.2 STATISTICAL HYPOTHESES 277
15.3 SAMPLING DISTRIBUTION OF D 277
15.4 t TEST 278
15.5 DETAILS: CALCULATIONS FOR THE t TEST 279
15.6 ESTIMATING EFFECT SIZE 281
15.7 ASSUMPTIONS 283
15.8 OVERVIEW: THREE t TESTS FOR POPULATION MEANS 283
15.9 t TEST FOR THE POPULATION CORRELATION COEFFICIENT, ρ
Summary 287
Important Terms 288
Key Equations 288
Review Questions 288
16
ANALYSIS OF VARIANCE (ONE FACTOR)
273
285
292
16.1
TESTING A HYPOTHESIS ABOUT SLEEP DEPRIVATION
AND AGGRESSION 293
16.2 TWO SOURCES OF VARIABILITY 294
16.3 F TEST 296
16.4 DETAILS: VARIANCE ESTIMATES 299
16.5 DETAILS: MEAN SQUARES (MS ) AND THE F RATIO 304
16.6 TABLE FOR THE F DISTRIBUTION 305
16.7 ANOVA SUMMARY TABLES 307
16.8 F TEST IS NONDIRECTIONAL 308
16.9 ESTIMATING EFFECT SIZE 308
16.10 MULTIPLE COMPARISONS 311
16.11 OVERVIEW: FLOW CHART FOR ANOVA 315
16.12 REPORTS IN THE LITERATURE 315
16.13 ASSUMPTIONS 316
16.14 COMPUTER OUTPUT 316
Summary 317
Important Terms 318
Key Equations 318
Review Questions 319
17
ANALYSIS OF VARIANCE (REPEATED MEASURES)
17.1
17.2
Witte11e_fm.indd 12
322
SLEEP DEPRIVATION EXPERIMENT WITH REPEATED MEASURES
F TEST 324
323
11/18/2016 8:18:13 PM
CONTENTS
xi i i
17.3 TWO COMPLICATIONS 325
17.4 DETAILS: VARIANCE ESTIMATES 326
17.5 DETAILS: MEAN SQUARE (MS ) AND THE F RATIO
17.6 TABLE FOR F DISTRIBUTION 331
17.7 ANOVA SUMMARY TABLES 331
17.8 ESTIMATING EFFECT SIZE 333
17.9 MULTIPLE COMPARISONS 333
17.10 REPORTS IN THE LITERATURE 335
17.11 ASSUMPTIONS 336
Summary 336
Important Terms 336
Key Equations 337
Review Questions 337
18
ANALYSIS OF VARIANCE (TWO FACTORS)
329
339
18.1 A TWO-FACTOR EXPERIMENT: RESPONSIBILITY IN CROWDS
18.2 THREE F TESTS 342
18.3 INTERACTION 344
18.4 DETAILS: VARIANCE ESTIMATES 347
18.5 DETAILS: MEAN SQUARES (MS ) AND F RATIOS 351
18.6 TABLE FOR THE F DISTRIBUTI …
Purchase answer to see full
attachment

  
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more