SCIENTIFIC METHODS an online book Richard D. Jarrard Dept. of Geology and Geophysics, University of Utah
[email protected] © Richard D. Jarrard 2001 Scientific Methods is an online book about the techniques and processes of science and the experience of being a scientist. This book is written by a scientist for scientists. My hope is that it will be browsed by scientists (including graduate students) and read by undergraduates. Why am I publishing this book online, despite having a willing soft-cover publisher? The main reason is wider availability to readers. A typical science book has a publication run of ~2000 copies, then it goes out of print. Additional factors include educational use and ease of revision. I admit that I would have enjoyed saying that I earned ~25¢/hour by writing this book. Feel free to print a personal copy of this book. Note, however, that this book is copyrighted; it is unethical (see Chapter 10) and illegal to distribute multiple printouts or digital copies or to copy any of these files to other web sites. CONTENTS 1. Introduction 1 Overview 1 Thumbnail History of Scientific Methods 3 Myth of a Scientific Method 12 Scientific Methods 12 SCIENTIFIC TOOLBOX 2. Variables 15 Statistics 15 Errors 16 Precision > Accuracy > Reliability 17 Random and Systematic Errors 18 Representative Sampling 18 Replication and Confirmation 20 Probability 20 Sampling Distribution for One Variable 21 Histograms 22 Normal Distribution 23 Mean & Standard Deviation 23 Normal Distribution Function 24 Weighted Mean 26 95% Confidence Limits on Mean 26 How Many Measurements are Needed? 27 Propagation of Errors 28 Non-Normal Distributions 29 Normality Tests 30 Rejecting Anomalous Data 32 Median, Range, & 95% Confidence Limits 33 Examples 37 3.