Statistics for Veterinary and Animal Science

by Petrie, Aviva; Watson, Paul

• ISBN13: 9780632050253
• ISBN10: 063205025X
• Format: Paperback
• Copyright: 1999-07-01
• Publisher: John Wiley & Sons Inc

Summary

Statistics is a subject that many veterinary and other animal science students approach with foreboding, but it is essential for them to grasp the basics in order to understand their subject and play a contributive part in it. This is true whether they be practitioners, research scientists, diagnosticians, or run commercial pathology services, work in research and development of veterinary drugs, or simply care for healthy animals in performance and production. The increasing need to keep up with the literature and to evaluate the competitive promotions for animal systems and health products requires that students have a sound foundation in biological statistics applied to animal care. The emergence of new diseases requires that risk factors associated with them are carefully evaluated.This introductory book will lead the reader through the basics and form a bridge to more complicated statistical procedures found in advanced texts. Written in a non-mathematical way, it contains numerous worked examples helping the reader to develop understanding of the procedures rather than simply the mechanical abilities to perform them.

Table of Contents

Preface	ix
The whys and wherefores of statistics	1	(10)
Learning objectives	1	(1)
Aims of the book	1	(1)
What is statistics?	2	(1)
Statistics in veterinary and animal science	3	(1)
Types of variable	3	(1)
Variations in measurements	4	(3)
Terms relating to measurement quality	7	(1)
Populations and samples	8	(1)
Types of statistical procedures	9	(1)
Conclusion	9	(2)
Exercises	9	(2)
Descriptive statistics	11	(16)
Learning objectives	11	(1)
Summarizing data	11	(1)
Empirical frequency distributions	11	(2)
Tables	13	(1)
Diagrams	13	(5)
Numerical measures	18	(6)
The reference range	24	(3)
Exercises	24	(3)
Probability and probability distributions	27	(17)
Learning objectives	27	(1)
Probability	27	(2)
Probability distributions	29	(1)
Discrete probability distributions	29	(3)
Continuous probability distributions	32	(9)
Relationships between distributions	41	(3)
Exercises	42	(2)
Sampling and sampling distributions	44	(9)
Learning objectives	44	(1)
The distinction between the sample and the population	44	(1)
Statistical inference	44	(2)
The sampling distribution of the mean	46	(2)
The confidence interval for a mean	48	(2)
The sampling distribution of the proportion	50	(1)
The confidence interval for a proportion	50	(3)
Exercises	51	(2)
Experimental design and clinical trials	53	(16)
Learning objectives	53	(1)
Types of study	53	(3)
Introducing clinical trials	56	(1)
The importance of design in the clinical trial	56	(1)
The control group	57	(1)
Assignment of animals to the treatment groups	58	(2)
The avoidance of bias in the assessment procedure	60	(1)
Increasing the precision of the estimates	61	(2)
Further considerations	63	(6)
Exercises	67	(2)
An introduction to hypothesis testing	69	(9)
Learning objectives	69	(1)
Introduction	69	(1)
Basic concepts of hypothesis testing	69	(4)
Type I and Type II errors	73	(1)
The distinction between statistical and biological significance	74	(1)
The confidence interval approach to hypothesis testing	75	(1)
Collecting our thoughts on confidence intervals	75	(3)
Exercises	76	(2)
Hypothesis tests 1 -- the t-test: comparing one or two means	78	(12)
Learning objectives	78	(1)
Requirements for hypothesis tests for comparing means	78	(2)
One-sample t-tests	80	(1)
Two-sample t-tests	81	(4)
The paired t-test	85	(5)
Exercises	88	(2)
Hypothesis tests 2 -- the F-test: comparing two variances or more than two means	90	(11)
Learning objectives	90	(1)
Introduction	90	(1)
The F-test for the equality of two variances	90	(2)
Levene's test for the equality of two or more variances	92	(1)
The analysis of variance (ANOVA) for the equality of means	92	(3)
One-way ANOVA	95	(6)
Exercises	99	(2)
Hypothesis tests 3 -- the Chi-squared test: comparing proportions	101	(13)
Learning objectives	101	(1)
Introduction	101	(1)
Testing a hypothesis about a single proportion	101	(1)
Comparing two proportions -- independent groups	102	(4)
Testing associations in an r x c contingency table	106	(3)
Comparing two proportions -- paired observations	109	(2)
The Chi-squared goodness-of-fit test	111	(3)
Exercises	112	(2)
Linear correlation and regression	114	(24)
Learning objectives	114	(1)
Introducing linear correlation and regression	114	(1)
Linear correlation	115	(5)
Simple linear regression	120	(9)
Multiple linear regression	129	(4)
Multiple logistic regression -- a binary response variable	133	(2)
Regression to the mean	135	(3)
Exercises	135	(3)
Non-parametric statistical tests	138	(15)
Learning objectives	138	(1)
Parametric and non-parametric tests	138	(2)
The sign test	140	(2)
Wilcoxon signed rank test	142	(2)
Wilcoxon rank sum test	144	(2)
Non-parametric analyses of variance	146	(2)
Spearman's rank correlation coefficient	148	(5)
Exercises	150	(3)
Further aspects of design and analysis	153	(15)
Learning objectives	153	(1)
Transformations	153	(3)
Sample size	156	(5)
Sample surveys	161	(3)
Multivariate analysis	164	(4)
Exercises	165	(3)
Additional topics	168	(14)
Learning objectives	168	(1)
Diagnostic tests	168	(2)
Measuring agreement	170	(5)
Measurements at successive points in time	175	(3)
Survival analysis	178	(4)
Exercises	179	(3)
Solutions to exercises	182	(12)
References	194	(3)
Appendices	197	(39)
A Statistical tables	198	(15)
B Tables of confidence intervals	213	(2)
C Flow charts for selection of appropriate tests	215	(3)
D Glossary of notation	218	(3)
E Glossary of terms	221	(15)
Index	236