Biology 2060: Statistics For Biologists

(Fall 2019)

 

 

LECTURES:  TUE. & THU. 10:30am - 11:30 LOCATION:  ACW 206

TUTORIALS: FRI. 2:30 - 5:30 LOCATION: ACW 206

COURSE DIRECTOR: Dr. Joel S. Shore, Professor of Biology

OFFICE HOURS AND HELP : during the latter portion of the tutorial and by appointment.

 

GRADING SCHEME:

Midterm 1 (20%)  Fri  4  Oct ACW 206

Midterm 2 (30%)  Fri 8 Nov ACW 206

Exam (50%)  Tue, 17 Dec TM Tait 2pm-5pm

 

 

 All your grades are posted on the link below. The grades listed are your raw scores on each of test 1 (out of 41) , test 2 (out of 40) and the final exam (out of 64). I have removed the first 3 digits from your student numbers and the last digit. So look carefully for your grades. The “official” letter grades are posted on the official York university website.

NOTE THAT IF YOU DID NOT WRITE THE FINAL EXAM A GRADE OF “F” HAS TO BE POSTED UNTIL SUCH A TIME AS YOU WRITE THE DEFERRED EXAM AT WHICH POINT THE GRADE IS CORRECTED.

All grades

 

 

Note that if you missed the final exam, you will be required to fill out a petition to write a deferred exam. This will mean that you will be writing the deferred (if granted) in the new year. Furthermore, I will be on sabbatical and therefore the deferred exam will not be handled by me and this will probably not be advantageous for you.

If you missed the final, please go to the undergraduate biology office in LSB 1st floor and/or email biology@yorku.ca

 

 

FINAL EXAM DETAILS

For the final exam, you may bring in ONE standard sheet of paper (8.5 inches x 11 inches) with anything you like written/printed on it, and you may use both sides of that single sheet of paper.

The final exam will cover all material since the course began, but will be very heavily weighted towards the material we have covered in the last two thirds of the course. The focus will largely be on hypothesis tests of all kinds. The material includes chapters 1 through 17 (excluding sections I’ve indicated that should be excluded in the course outline and/or in class) and all problem sets. SAS will be included as well. (As I’ve stated many times in class, make certain you conclude all hypothesis tests with a concluding statement referring to the data and/or means, or comparing observed versus expected, etc.).

The exam will be 180 minutes in duration. Roughly 13 questions. Statistical tables will be provided. Bring your calculator.

Make certain you find the exam room before the morning of the test so that you are not lost, and end up arriving late.

 

 

 

 

 

TEST 2 ANSWERS

TEST 2 DESCRIPTIVE STATS FROM PROC UNIVARIATE

TEST 2 GRADES OUT OF 40

 

 

Test 1 ANSWERS

TEST 1 GRADE SUMMARY STATS AND HISTOGRAM

GRADES

 

Missed midterm test policy:

There will be no make-up for the “mid-term” tests in this course. Students who miss a test must have legitimate medical documentation describing their illness. If the medical documentation is deemed to be legitimate the percent value of the missed test will be added to that student’s final exam (e.g. if you were hospitalized and could not write the second midterm test, and you provided legitimate medical documentation, then your final exam would be worth 80% or your grade).

 

REQUIRED TEXT BOOK

Whitlock and Schluter 2015. THE ANALYSIS OF BIOLOGICAL DATA, 2nd edition. Roberts and Company, Publishers.*

(buy it and begin reading!). We will largely follow the text from the beginning up to and including at least chapter 17. But see below for explicit details of which chapters and sections.

*Note that if you have a copy of the 1st edition of this book, it may suffice, but it is your responsibility to ensure that all the material in the 2nd edition that we cover, is indeed covered in the 1st edition.   

 

TUTORIALS

The tutorials will be devoted to a number of tasks including:

1) Taking up problem sets assigned throughout the course.

2) Learning to use the statistical computing software SAS.

3) Midterm tests will be written during the tutorial period.

4) Dealing with individual problems/questions of students

 

LEARNING OUTCOMES

Statistics is an extremely important field for biology, and many other disciplines.

By the end of this course students should be able to:

1)      Provide a summary of categorical and numeric data using graphical methods and statistics

2)      Apply the most powerful hypothesis test(s) to data from a range of biological experiments involving categorical or numeric data.

3)      Test the assumptions of various hypothesis tests

4)      Interpret the results of the hypothesis tests carried out

5)      Carry out the hypothesis tests both by “hand” and using the statistical computer program called SAS

 

SOME ADVICE ON HOW TO SUCCEED IN THIS COURSE

1)    ACQUIRE A COPY OF THE TEXTBOOK AND USE IT! YOU ARE RESPONSIBLE FOR ALL CHAPTERS IN THE BOOK INDICATED BELOW AND ALL MATERIAL IN THOSE CHAPTERS UNLESS I EXPLICITLY EXCLUDE CERTAIN PAGES/SECTIONS (SEE COURSE OUTLINE BELOW).

 

2)    ATTEND ALL LECTURES AND TUTORIALS, AND IF YOU MISS A CLASS MAKE ABSOLUTELY CERTAIN YOU CONTACT ANOTHER STUDENT(S) AND FIND OUT WHAT WAS COVERED, AND OBTAIN THEIR NOTES. IT IS YOUR RESPONSIBILITY TO FIND OUT WHAT WAS COVERED IN YOUR ABSENCE.

 

3)    AT A MINIMUM, DO ALL THE PROBLEM SETS, AND BETTER, DO AS MANY PROBLEMS/QUESTIONS AS YOU CAN. I’D HYPOTHESIZE THAT IF YOU DO TEN PROBLEMS OF EACH KIND, YOU SHOULD DO WELL IN THE COURSE BUT THIS MIGHT VARY FROM ONE STUDENT TO THE NEXT.

 

4)    USE THE STATISTICAL PROGRAM (SAS) TAUGHT DURING THIS COURSE. IT WILL BE A SIGNIFICANT/IMPORTANT TOOL IN THIS COURSE, AND WELL BEYOND.

 

5)    THIS COURSE MOVES AT AN ACCELERATED RATE. MAKE CERTAIN YOU KEEP UP OR YOU WILL BE LOST VERY SOON.

 

COURSE OUTLINE

1) INTRODUCTION TO STATISTICS (read chapter 1)

What is statistics?

Populations and samples

Random sampling

Types of data - categorical versus numeric

Explanatory versus Response variables

Frequency and probability distributions

2) DISPLAYING DATA (read chapter 2)

Plotting frequency distributions

Bar graphs, histograms

Contingency tables

Scatterplots for two variables

3) DESCRIBING DATA (read chapter 3)

Sample mean and sample median

Variance and standard deviation

(computational formula)

Quartiles and box plots

Cumulative frequency distribution

Proportions

4) Estimation with uncertainty (read chapter 4)

Estimating a population parameter

Sampling distribution of the estimates

e.g. mean

Standard error

Confidence intervals

5) Probability (read chapter 5 sections 5.1 through 5.8 inclusive)

Probability of events

Mutually exclusive events

Probability distributions

Addition and multiplication rules

Independent events

Probability trees

Pseudoreplication (read pgs 115-116)

6) Hypothesis testing (Chapter 6 & 7)

Null (Ho) versus Alternative (Ha) hypotheses

One versus two-sided tests

Examples

Handedness and Chlorophyll

P-value

Type I and Type II errors

Analysing proportions and hypothesis tests using the Binomial distribution

OMIT THE MATERIAL ON CALCULATING CONFIDENCE INTERVALS FOR PROPORTIONS ON PAGES (189-191).

7) Goodness-of-Fit and Contingency tests (Chapters 8 & 9)

X2 goodness-of-fit tests

assumptions

examples

Fitting data to probability distributions

Contingency tests

G-statistic

OMIT SECTION 9.2 ON ESTIMATING ASSOCIATION IN 2X2 TALBES: ODDS RATIOS

8) The normal distribution (Chapter 10)

Ignore normal approximation for the binomial distribution (section 10.7)

The standard normal distribution and probabilities

Normal distribution of sample means

Central limit theorem

 

9) Student's t-test (Chapter 11 & 12)

the t-distribution

confidence intervals

one- and two-sample t-tests

assumptions

paired t-test

F-test of equal variances

OMIT SECTION 11.5 ON CONFIDENCE LIMITS FOR VARIANCE AND STANDARD DEVIATION

10) Violations of assumptions, transformation and non parametric tests (Chapter 13)

Detecting deviations from normality read section, but won't carry out Shapiro Wilk test for normality.

Transforming data to meet normality assumption

Non-parametric alternatives to t-tests

Ignore chapter 14.

11) Analysis of Variance (Chapters 15)

Single factor ANOVA

Planned versus unplanned comparisons

Fixed versus random effects

(Ignore Nonparametric alternatives pg. 471, but you should know of their existence and when to use them).

 

12) Correlation and Regression (Chapter 16 and 17)

Chpt 16 only sections 16.1 ( but ignore confidence interval material)

include 16.2, 16.3, 16.4

Chpt 17 only sections 17.1 (ignore confidence interval)

include 17.3 (ignore ANOVA approach).

Correlation coefficient

Linear regression

Estimation of least squares line

Hypothesis test of slope

Assumptions and transformations

13) Recent advances in statistics

 

 

TUTORIAL ASSIGNMENTS:

PROBLEM SET 1

Answers problem set 1

PROBLEM SET 2 

Answers problem set 2                    

Some potentially useful function/operations in SAS

Computational formulae for sample variance and standard deviation

PROBLEM SET 3

Answers problem set 3

PROBLEM SET 4

Answers problem set 4

PROBLEM SET 5

Answers problem set 5

PROBLEM SET 6

Answers problem set 6

PROBLEM SET 7

Answers problem set 7

PROBLEM SET 8                  

Answers problem set 8

For ANOVA, Correlation and Regression, see the three items below

Computational formulae for anova and correlation

Computational formulae for simple linear regression

Some regression diagnostics

 

I have posted some lectures below as youtube “videos”. These were not made this year but were made two years ago. They should, however be fairly close to the lectures given this year.

1. paired t-test

2. independent sample (2-sample) t-test

3. F-test to compare two variances

4.a Violations of Assumptions, transformations, non-parametric tests 1

   b. Violations of Assumptions, transformations, non-parametric tests 2

5. a. Analysis of Variance, overview, computational equations, example

    b. Anova, linear models, fixed vs random effects, F-tables

    c. Anova, Example, R-squared, apriori test

    d. Anova, Tukey Kramer aposteriori test, variance components

6. Correlation

7. Linear Regression

8. Review of course, which hypothesis test, “advanced” methods

 

 

IMPORTANT COURSE INFORMATION FOR STUDENTS (copied from the Senate Committee on Academic Standards, Curriculum & Pedagogy BASIC COURSE OUTLINE MODEL)

 

All students are expected to familiarize themselves with the following information, available on the Senate Committee on Academic Standards, Curriculum & Pedagogy webpage (see Reports, Initiatives, Documents) 

   http://www.yorku.ca/secretariat/senate/committees/ascp/index-ascp.html

 

·         Senate Policy on Academic Honesty and the Academic Integrity Website

·         Ethics Review Process for research involving human participants 

·         Course requirement accommodation for students with disabilities, including physical, medical, systemic, learning and psychiatric disabilities

·         Student Conduct Standards

·         Religious Observance Accommodation

 

IMPORTANT DATES

 

https://registrar.yorku.ca/enrol/dates/fw19

 

Students who feel that there are extenuating circumstances that may interfere with their ability to successfully complete the course requirements are encouraged to discuss the matter with the Course Director as soon as possible.

 

Academic Honesty and Integrity

York students are required to maintain the highest standards of academic honesty and they are subject to the Senate Policy on Academic Honesty (http://secretariat-policies.info.yorku.ca/policies/academic-honesty-senate-policy-on/). The Policy affirms the responsibility of faculty members to foster acceptable standards of academic conduct and of the student to abide by such standards.

There is also an academic integrity website with comprehensive information about academic honesty and how to find resources at York to help improve students’ research and writing skills, and cope with University life. Students are expected to review the materials on the Academic Integrity website at - http://www.yorku.ca/academicintegrity/

 

Important A note from the Faculty of Science Committee on Examinations and Academic Standards:

Numerous students in Faculty of Science courses have been charged with academic misconduct when materials they uploaded to third party repository sites (e.g. Course Hero, One Class, etc.) were taken and used by unknown students in later offerings of the course. The Faculty’s Committee on Examinations and Academic Standards (CEAS) found in these cases that the burden of proof in a charge of aiding and abetting had been met, since the uploading students had been found in all cases to be wilfully blind to the reasonable likelihood of supporting plagiarism in this manner. Accordingly, to avoid this risk, students are urged not to upload their work to these sites. Whenever a student submits work obtained through Course Hero or One Class, the submitting student will be charged with plagiarism and the uploading student will be charged with aiding and abetting.

 

Note also that exams, tests, and other assignments are the copyrighted works of the professor assigning them, whether copyright is overtly claimed or not (i.e. whether the © is used or not). Scanning these documents constitutes copying, which is a breach of Canadian copyright law, and the breach is aggravated when scans are shared or uploaded to third party repository sites.

 

Access/Disability

York University is committed to principles of respect, inclusion and equality of all persons with disabilities across campus. The University provides services for students with disabilities (including physical, medical, learning and psychiatric disabilities) needing accommodation related to teaching and evaluation methods/materials. These services are made available to students in all Faculties and programs at York University.

Student's in need of these services are asked to register with disability services as early as possible to ensure that appropriate academic accommodation can be provided with advance notice. You are encouraged to schedule a time early in the term to meet with each professor to discuss your accommodation needs. Please note that registering with disabilities services and discussing your needs with your professors is necessary to avoid any impediment to receiving the necessary academic accommodations to meet your needs.

Additional information is available at the following websites:

Counselling & Disability Services - http://cds.info.yorku.ca/

Counselling & Disability Services at Glendon - https://www.glendon.yorku.ca/counselling/

York Accessibility Hub - http://accessibilityhub.info.yorku.ca/

 

Religious Observance Accommodation

York University is committed to respecting the religious beliefs and practices of all members of the community, and making accommodations for observances of special significance to adherents. Should any of the dates specified in this syllabus for an in-class test or examination pose such a conflict for you, contact the Course Director within the first three weeks of class. Similarly, should an assignment to be completed in a lab, practicum placement, workshop, etc., scheduled later in the term pose such a conflict, contact the Course director immediately. Please note that to arrange an alternative date or time for an examination scheduled in the formal examination periods (December and April/May), students must complete and submit an Examination Accommodation Form at least 3 weeks before the exam period begins. The form can be obtained from Student Client Services, Student Services Centre or online at http://www.registrar.yorku.ca/pdf/exam_accommodation.pdf

 

Student Conduct in Academic Situations

Students and instructors are expected to maintain a professional relationship characterized by courtesy and mutual respect. Moreover, it is the responsibility of the instructor to maintain an appropriate academic atmosphere in the classroom and other academic settings, and the responsibility of the student to cooperate in that endeavour. Further, the instructor is the best person to decide, in the first instance, whether such an atmosphere is present in the class. The policy and procedures governing disruptive and/or harassing behaviour by students in academic situations is available at - http://secretariat-policies.info.yorku.ca/policies/disruptive-andor-harassing-behaviour-in-academic-situations-senate-policy/