1) To estimate the mean number of people who are admitted to the
emergency room in Hamad
2
= 9. The 99% confidence
interval is:
A) 20.2 0.699
B) 20.2 0.4935 C) 20.2 0.7725
D) 20.2 0.384
2) Use the confidence level and sample data to find the margin of err
Qatar University
Applied Survival Analysis
Date: 11/11/2015
Statistics Program
Assignment 3
Due date: 16/11/2015
-Student Names:
Group Number:
-Consider the following survival data on 15 patients containing their survival times in weeks, gender
(male = 0,
Find the following probabilities: Pr(A), Pr(A or B), Pr(C and D),
Pr(D and E), Pr(D or E)
Probability Trees
Probability tree is a convenient way to break a problem down into
parts and organize information.
Example 7
A family has two children if the probab
Effects of Transformations of Variables
There are a lot of reasons why it is more convenient to transform
a variable some of those reasons include:
1. You may want to change units from kg to
lbs
2. Your number may be very small such as
6.023.10-23 may b
Normal Curves
Normal distribution: is a distribution represented by a normal curve.
If a variable Y follows normal distribution, then it can be represented by
Y ~ N ,
.
N represents that the distribution is normally distributed,
represents the population
Hm Enlnr and he Eula: Table 3.3.1 sham the mhtiumhip helm hair mint and
1:: mlur in: a Err-up at 1.170 Gennnn mm.
'I'IHI 1.2M Hltr CHIIH' Ind are cutw
tn Baum Em hlwk hair and wd hair" an: ninL if we chum inmemu:
at madam from thin Emup then Priblhct hair
Probability and the Life Sciences
When we are studying probability, we are
determining the likelihood of a certain situation
taking place.
Combining that with the Life Sciences, we could be looking
at the likelihood of two human parents with brown eyes
ha
Computing Formula for a Sample Standard Deviation
A sample standard deviation can be computed using the
computing formula s .
=
( ) (
(
1
)
2
)
Comparison of Measures of Dispersion?
Grouped-Data Formulas
When data are grouped in a frequency distribution,
Binomial Distributions
This section focuses on a special type of a random variable
called the binomial.
In some statistical studies we perform an experiment
repeatedly. In this type of experiment, there are only two
outcomes. These two outcomes are either
Applied Survival Analysis
Date: 18/11/2015
Statistics Program
Assignment 3
Due date: 23/11/2015
-Student Names:
Group Number:
-The data for this question consists of a sample of 50 persons from the 1967-1980 Evans County
Study. There are two basic indepen
50
1.
Introduction to Survival Analysis
Practice
Exercises
True or False (Circle T or F):
T
F
T
F
T
F
T
F
T
T
T
F
F
F
T
F
T
F
T
F
T
F
T
F
T
T
F
F
T
F
1. In a survival analysis, the outcome variable is
dichotomous.
2. In a survival analysis, the event is u
1)
The following table cross-classies 6549 subjects living in Massachusetts according to health
risk (stressed or not stressed) and income (low, medium, or high):
Income
Stress level Low Medium High Total
Stressed 526 274 216 1016
Not Stressed 1954 1680 1
1) The brain weights of a certain population of adult Swedish males follow a normal
distribution with mean = 1400g and standard deviation = 100g.
a) What percentage of the brain weights for this population are between 1200 and
1600 grams?
b) What is the 8
Chapter 3
Random Sampling, Probability, and the Binomial Distribution.
Random Samples
Definition:
A SIMPLE RANDOM SAMPLE of n items is a data set
where:
(a) every member of the population has an
equal
chance of being selected.
(b) the members of the sampl
Descriptive Statistics
Measures of Center
Measures of center include:
the m
ean
the m
edian
the m
ode
These m
easures all describe the center of a distribution in a slightly different way.
Sample Mean
Definition:
The mean of a data set is the sum of the o
The Normal Distribution
Chapter 4:
Definition:
A continuous random variable Y has a NORMAL
DISTRIBUTION if its probability density can be written as:
2
2
1 e -(y-Y) /2Y
f (y) =
Y 2
over
< y < .
NOTATION: Y ~ N(Y , 2 Y)
The mean and variance of a normal d
Exercise:
A random sample of 3,500 eligible voters was asked whether they
approved of the president's job performance. Here are the results:
A. Find P(Fem
ale) and P(Male).
B. Find P(Approve) and P(Disapprove).
C. Find P(Fem | Approve) and P(Male | Approv
Chapter 5:
Sampling
Distributions
Sampling distributions
Study and meta-study
Sampling distribution of a proportion
Estimator for a Proportion
For Y ~ Bin(n,p) we can estimate p if it is unknown
using the SAMPLE PROPORTION:
p=Y
n
Since Y is random, so is
Chapter 7
Comparison Of Two Independent
Samples
Notation for comparison of two samples
Hypothesis testing
A statistical hypothesis test is a method of making
decisions using data.
Example:
Scientists wish to test the hypothesis that norepinephrine (NE)
le
Chapter 6:
Estimation and Confidence
Intervals
Unbiased Estimation
Parameters such as
or are usually unknown, and
we use the sample data to estimate them.
Definition: If an estimator
parameter
of an unknown
E =
has the property that
we say it is an UNB