STAT 3843A Fall 2013
Assignment 2
Due: October 11 on paper in class
1. For any sampling scheme, i is the probability that unit i is selected.
The HorvitzThompson estimator of the population total t is t =
iS yi /i .
(a) Show that the SRS estimate t = N y
Intro to study design lecture 28
3 factor interaction is a tetrahedron
Shouldnt use factorial model when you have a outlier ( e.g mistake in your data recording)
*exam will give you a picture and ask you what is it measuring (cube)
only looking at high le
Topics covered in SS 3843a, Fall 2013, up to midterm.
1. Long form census controversy
Arguments for a mandatory census: less selection bias, more ecient than many small surveys, needed as a reference.
Arguments for optional survey: questions are intrusi
Intro to study design lecture 31
Unusual informed consent procedure
Randomized patients to ECMO or CMT 1st
Only ECMO patients (then patients) wre asked for consent

Better to ask CMT patients for consent too and let htem know hte possible outcome for eac
Intro to study design lecture 32
We calculated 28 pvalues (from uniform (0,1)
Smallest was
Distribution of smallest pvalue is not uniform, there is about a 70% chance of being a significant
one.
Bongerroni correction:
Do all tests at 0.05/28 level, so o
Intro to study design lecture 8
Suppose n=1, * box sometimes this is called the population variance. We say
SRS (simple random survey without replacement)
Define sample mean:
However, this is hard to calculate, so nice trick. Define
Then,
Therefore,
as
is
Intro to study design lecture 6
Requirements for a good sample
Observation unit
Target population
Sample
Sampled population
Sampling unit
Sampling frame
Selection bias
Measurement bias

Bias in the observation on an observation unit
o A miscalibrated sca
Intro to study design lecture 5
Sample survey
Measure only a sample from a population.
What is a good sample to choose?
o You want it to be representative
i.e characteristics of the sample matches the population
types of samples
o voluntary response samp
Intro to study design lecture 30/11
Bayesian interim analysis
Simple model
treatment difference.
good
bad
Prior idea for ,
Model
Posterior distribution
Now
(likelihood data density) since i.i.d, and
Now,
is our prior density
doesnt depend on , you can tr
Intro to study design lecture 7
Probability sampling (Loh chapter 2)
Convenience samples tend to be biased. Probablity samples are an alternative
Simple random samples (SRS)

Randomly choose in units out of the sampling frame (or population) of N units
E
Intro to study design lecture 21 31/oct
the completely randomized design
t treatments
r replicates of each treatment
rt units assigned at random
simple model
Research question
Does the treatment affect
? i.e are all the
To address this, fit the model wit
Intro to study design lecture 16
Administrative data data that were collected for a non statistical purpose.
Guidelines from statcan continued:

Look particularly at items you prepare to use
Questions like occupation might be recorded too coarsely
Admini
Clinical trails
Planned experiments to access the most appropriate medical treatment for future patients
Treatments: drug, surgical procedure, other therapy
Outcomes:
Labs test results
qualify of life measure
Survival on other major outcome
Nowadays, clin
Validity of statistical studies (week 2, Wednesday lecture 3)
Experiment 1
Hydrogen
and oxygen
in two test tubes.
s/he applies heat to one of them
the heated tube gives a pop & forms water vapour
Conclusion
Is the heat caused the water to form
Seems like
STAT 3843A Fall 2013
Assignment 4
Due: November 15 in class
1. An agricultural experiment was done to determine the eect of nitrogen
fertilizer on the production of lettuce. Five dierent levels of ammonium nitrate fertilizer were used, and the resulting y
Topics covered in SS 3843a, Fall 2013.
1. Long form census controversy
Arguments for a mandatory census: less selection bias, more ecient than many small surveys, needed as a reference.
Arguments for optional survey: questions are intrusive, shouldnt
co
There are two suggested questions.
Sample survey analysis
1. Which of the following SRS designs will give the most precision for estimating
a population mean? Assume that each population has the same value of the
population variance
S2 .
a. An SRS of size
1. Ethics principles to conduct a study
(1). Studies should immunize harm.
(2) Participants should be volunteers
(3) Participants should be able to draw out any time.
(4) Informed consent from participants
(5) Keep individual data confidential
(6) Employe
SS 3843a Final Exam
Name:
ID:
1
Department of Statistical and Actuarial Sciences
SS 3843a Fall 2012
Instructor: D. Murdoch
Final Exam December 15, 710 PM
Instructions
A basic calculator is allowed; no other aids are allowed. Cell phones, pagers and othe
There are two suggested questions.
Sample survey analysis
1. Which of the following SRS designs will give the most precision for estimating a
population mean? Assume that each population has the same value of the population
variance
S2 .
a. An SRS of size
1.why we need to do stratified sampling? (A)
(1) cost less for the same accuracy than SRS.
(2) Protected from really bad random samples.
(3) we need different types of measurement in different strata.
(4) Want data about the subgroup and we want control t
STAT 3843A Fall 2013
Assignment 1
Due: September 27 in class
One of the following questions is taken from the Lohr textbook. Reading
that material will help in answering it!
1. Get a copy of the National Household Survey (NHS) from
http:/www12.statcan.gc.
Question suggestions for final exam:
a. Name 5 of the 10 principles of privacy protection from the Canadian
Code of Practice for Consumer Protection in Electronic Commerce.
b. Name 3 reasons why we conduct experiments.
c. Describe each of the four phases
STAT 3843A Fall 2013
Assignment 3
Due: October 25 in class
Read the October 7 news release from Forum Research predicting the
Nova Scotia election. A link and an archived copy of it are on the OWL
page. Also nd the nal ocial results on the Elections Nova
STAT 3843A Fall 2013
Assignment 5
Due: November 29 in class
1. (Based on a Box Hunter Hunter problem) In an experiment the objective was to nd the eects of changes to various factors on the amount
of unburned carbon in engine exhaust gas. The following re
Intro to study design lecture 23 5th nov
Factorial design
Treatments are made up of factors.
Example: drug test
Factor1: drug A vs drug B
Factor2: pill vs injection
Factor3: frequency: one dose/day vs two dose/day
With 3 factors, each at 2 levels, there a
Intro to study design lecture 13
Should you stratify?
Some reasons?
Total data
May be able to optimize costs
It might reduce the variance of
When does it do this?
Assume
This leads to proportional allocation
We want to compare
to
Think as though were usin
Lecture 12
Allocating
When
values
are all the same, allocate
(nearest integer value)
We had
If all
To choose
values to minimize this, minimize
A more realistic model of sampling
varies from stratum to stratum. Treat these as known (maybe coming from a pil
Study design lecture 25
2)level factorial designs: k factors on two levels
With k=2,
For higher k, the models are similar, but just more complicated. We wont write them.
To calculate a main effect:
Since
We get
Watch out
The BHH book defines
to be the eff