Choosing and Using Statistics

Choosing and Using Statistics remains an invaluable guide
for students using a computer package to analyse data from research
projects and practical class work. The text takes a pragmatic
approach to statistics with a strong focus on what is actually
needed. There are chapters giving useful advice on the basics
of statistics and guidance on the presentation of data. The book is
built around a key to selecting the correct statistical test and
then gives clear guidance on how to carry out the test and
interpret the output from four commonly used computer packages:
SPSS, Minitab, Excel, and (new to this edition) the free program,
R. Only the basics of formal statistics are described and the
emphasis is on jargon-free English but any unfamiliar words can be
looked up in the extensive glossary. This new 3rd
edition of Choosing and Using Statistics is a must for all
students who use a computer package to apply statistics in
practical and project work.

Features new to this edition:

• Now features information on using the popular free program,
  R

• Uses a simple key and flow chart to help you choose the right
  statistical test

• Aimed at students using statistics for projects and in
  practical classes

• Includes an extensive glossary and key to symbols to explain
  any statistical jargon

• No previous knowledge of statistics is assumed

Autorentext
Calvin Dytham has a wide range of research interests in ecology and evolutionary biology and is especially interested in the impacts of dispersal and the arrangement of individuals in space on ecological and evolutionary processes. He is a Reader in the Department of Biology at the University of York, UK, and has been teaching statistics to undergraduate and postgraduate students since 1994.

Klappentext
Choosing and Using Statistics remains an invaluable guide for students using a computer package to analyse data from research projects and practical class work. The text takes a pragmatic approach to statistics with a strong focus on what is actually needed. There are chapters giving useful advice on the basics of statistics and guidance on the presentation of data. The book is built around a key to selecting the correct statistical test and then gives clear guidance on how to carry out the test and interpret the output from four commonly used computer packages: SPSS, Minitab, Excel, and (new to this edition) the free program, R. Only the basics of formal statistics are described and the emphasis is on jargon-free English but any unfamiliar words can be looked up in the extensive glossary. This new 3rd edition of Choosing and Using Statistics is a must for all students who use a computer package to apply statistics in practical and project work. Features new to this edition:

• Now features information on using the popular free program, R
• Uses a simple key and flow chart to help you choose the right statistical test
• Aimed at students using statistics for projects and in practical classes
• Includes an extensive glossary and key to symbols to explain any statistical jargon
• No previous knowledge of statistics is assumed

Inhalt
Preface xiii The third edition xiv

How to use this book xiv

Packages used xv

Example data xv

Acknowledgements for the first edition xv

Acknowledgements for the second edition xv

Acknowledgements for the third edition xvi

1 Eight steps to successful data analysis 1

2 The basics 2

Observations 2

Hypothesis testing 2

P-values 3

Sampling 3

Experiments 4

Statistics 4

Descriptive statistics 5

Tests of difference 5

Tests of relationships 5

Tests for data investigation 6

3 Choosing a test: a key 7

Remember: eight steps to successful data analysis 7

The art of choosing a test 7

A key to assist in your choice of statistical test 8

4 Hypothesis testing, sampling and experimental design 23

Hypothesis testing 23

Acceptable errors 23

P-values 24

Sampling 25

Choice of sample unit 25

Number of sample units 26

Positioning of sample units to achieve a random sample 26

Timing of sampling 27

Experimental design 27

Control 28

Procedural controls 28

Temporal control 28

Experimental control 29

Statistical control 29

Some standard experimental designs 29

5 Statistics, variables and distributions 32

What are statistics? 32

Types of statistics 33

Descriptive statistics 33

Parametric statistics 33

Non-parametric statistics 33

What is a variable? 33

Types of variables or scales of measurement 34

Measurement variables 34

Continuous variables 34

Discrete variables 35

How accurate do I need to be? 35

Ranked variables 35

Attributes 35

Derived variables 36

Types of distribution 36

Discrete distributions 36

The Poisson distribution 36

The binomial distribution 37

The negative binomial distribution 39

The hypergeometric distribution 39

Continuous distributions 40

The rectangular distribution 40

The normal distribution 40

The standardized normal distribution 40

Convergence of a Poisson distribution to a normal distribution 41

Sampling distributions and the 'central limit theorem' 41

Describing the normal distribution further 41

Skewness 41

Kurtosis 43

Is a distribution normal? 43

Transformations 43

An example 44

The angular transformation 44

The logit transformation 45

The t-distribution 46

Confidence intervals 47

The chi-square distribution 47

The exponential distribution 47

Non-parametric 'distributions' 48

Ranking, quartiles and the interquartile range 48

Box and whisker plots 48

6 Descriptive and presentational techniques 49

General advice 49

Displaying data: summarizing a single variable 49

Box and whisker plot (box plot) 49

Displaying data: showing the distribution of a single variable 50

Bar chart: for discrete data 50

Histogram: for continuous data 51

Pie chart: for categorical data or attribute data 52

Descriptive statistics 52

Statistics of location or position 52

Arithmetic mean 53

Geometric mean 53

Harmonic mean 53

Median 53

Mode 53

Statistics of distribution, dispersion or spread 55

Range 55

Interquartile range 55

Variance 55

Standard deviation (SD) 55

Standard error (SE) 56 Confidence intervals (CI) or c...