9/22/2013
Flip a coin 3 times and record the number
of heads (H).
Q: Is the coin fair?
Roll 2 dice and record the outcome.
Q: What is chance of double sixes?
Suppose you are a welder exposed to
fumes.
Q: What is the chance you develop
Parkinsons Disease?
1
The Statistical Sleuth, Chapter 20 (Ramsey
and Schafer)
2
On January 28, 1986 the space shuttle Challenger
exploded ~70 seconds after the launch
Seven astronauts died
The explosion was caused by two rubber O-rings
that leaked
The temperature on that day
10/27/2013
Remember that statistical inference is about making
conclusions about a population parameter or population
parameters, based on information from a representative
sample or representative samples
What is needed therefore is to know, under repeat
12/4/2013
In 1846, the Donner and Reed families left
Springfield, Illinois for California in covered
wagons. When they reached Fort Bridger, Wyoming,
the leaders decides to try a new route to
Sacramento. They were stranded in the eastern
Sierra Nevada mou
1
What is Multiple Comparisons?
When do we have to adjust for multiple
comparisons?
How do we adjust for multiple comparisons in
R?
Sections 9.1, 9.2, 9.3, 9.5, 9.7, 9.10
2
Recall possible errors in hypothesis testing:
Null is declared
TRUE
Null hypothesi
1
X, Y are two random variables having the
same distribution and the same variance
We want to know if the means of X and Y are
the same
How can we test mx=my?
A reasonable test statistic may be
2
What is the variance of X-Y ?
In general, V(XY) = V(X) +
10/14/13
Develop point estimates for the population variance
Construct confidence intervals for the population
variance
Perform one-sample tests for the population
variance
Perform two-sample tests for the population
variance
Note: Need to assume n
10/20/2013
Assumptions:
Normality of the data or large sample
sizes
Independence of observations within each
sample and between samples
Equal or unequal variance assumptions
For small sample sizes and non-normal
data: nonparametric methods: Wilcoxon
s
10/6/2013
1
In 1943, the U.S. military set up an enterprise near
Richland, Wash., to create plutonium for warheads.
Through 1989, activities at Hanford Reservation
yielded at least 55 million gallons of high-level
radioactive wastes-more than half the tot
8/27/2013
Population the set of all measurements of
interest to the sample collector
Sample any subset of measurements
selected from the population
The statisticians goal is to draw certain
conclusions about the population, but only a
subset is available