BIOL 300: Biostatistics
Statistical quotations There are three kinds of lies: lies, damn lies, and statistics. –Benjamin Disraeli / Mark Twain
Statistical quotations There are three kinds of lies: lies, damn lies, and statistics. –Benjamin Disraeli / Mark Twain It is easy to lie with statistics, but easier to lie without them. –Frederick Mosteller
Professor: Dr. Luke Harmon Department of Zoology Office: 1370 Biosciences Office Hours: pm Mondays (or after class)
Course website Lecture notes Textbook and Lab Manual Assignments and answers Contact information
Textbook Whitlock and Schluter, The analysis of biological data Available in two installments at CopieSmart, UBC Village Also available online
JMP Optional statistical software Used in labs Available in bookstore 60-day trial version on web:
Evaluation Final 50% Mid-term 30% Assignments (homework) 10% Lab exam (final week of term) 10%
Examinations Midterm: Thursday October 19 in class Final exam: TBA Old exams will be posted on the website
Assignments Available on course web-page, announced in class Due on Fridays at noon, at your TA’s office (eight days after they are assigned) Bonus points for in-class quizzes and activities
Lab Begins third week of term (September ) Biol. Sci. room 2434 Lab exam during final week of classes Book available at Copiesmart in the village and online
Class Forum There will be a forum for discussion on the web Discussion of lectures, labs, and homework More details available next week
STATISTICS PAIRINGS Credit given for only one of BIOL 300, FRST 231, STAT 200, PSYC 218 or 366. These are paired with BIOL 300, but do not count as requirements for Biology majors and pre-reqs
Introduction to statistics Statistics - technology used to describe and measure aspects of nature from samples Statistics lets us quantify the uncertainty of these measures
The history of statistics has its roots in biology
Sir Francis Galton Inventor of fingerprints, study of heredity of quantitative traits Regression & correlation Also: efficacy of prayer, attractiveness as function of distance from London
Karl Pearson Polymath- Studied genetics Correlation coefficient 2 test Standard deviation
Sir Ronald Fisher The Genetical Theory of Natural Selection Founder of population genetics Analysis of variance likelihood P-value randomized experiments multiple regression etc., etc., etc.
Goals of statistics Estimation –Infer an unknown quantity of a population using sample data Hypothesis testing –Differences among groups –Relationships among variables
Statistics is also about good scientific practice
Introductory Puzzle How to protect bombers flying over enemy territory? British Air Ministry - WWII Looked at distribution of bullet holes in airplanes returning from bombing runs
Results Where should more armor be added to the airplanes? Explain your conclusion
Variable A variable is a characteristic measured on individuals drawn from a population under study. Data are measurements of one or more variables made on a collection of individuals.
Explanatory and response variables We try to predict or explain a response variable from an explanatory variable.
Mortality on the Titanic, as predicted by sex
Populations and samples
Populations Parameters; Samples Estimates
Nomenclature Population Parameters Sample Statistics Mean Variance s2s2 Standard Deviation s
Properties of a good sample Independent selection of individuals Random selection of individuals Sufficiently large
In a random sample, each member of a population has an equal and independent chance of being selected.
Bias is a systematic discrepancy between estimates and the true population characteristic.
A sample of convenience is a collection of individuals that happen to be available at the time.
Sampling error The difference between the estimate and average value of the estimate
Population parameters are constants whereas estimates are random variables, changing from one random sample to the next from the same population.
Larger samples on average will have smaller sampling error
Read: Chapters 1 & 2