1.6:
Make this histogram by hand. as the instructions suggest:
State Percentages Aged 35 and Over. 20119
F'WWFW
IU
Partner"
1.34: (a) A histogram is provided below. (b) This is an extremely right-skewed distribution.
Ratios greater than 1 co
STAT 201 Quiz 2
May 23, 2003
Student #:
Name:
BLANK SPACE
A news article on the Reuters Health website, Dec. 18, 1998 reported:
A study of over 1200 people over age 65 showed that the owls those who go to
sleep after 11 pm and rise after 8 am tend to be a
* Analyses *
There are three basic types of parameters of interest for basic
statistics, mean, proportions, and slopes.
Common SAS procedures for doing analyses on MEAN include
Proc TTEST (comparing means between 2 groups)
Proc GLM (comparing means betwee
Contingency Tables
Chapter 22.
Experiment:
Fifty streams examined.
Each classied in two ways:
1) Slow owing or fast owing?
2) Weed choked, some weeds, shingle or silt?
Results in 2 4 contingency table.
Slow Flow
Fast Flow
Total
Weed
Choked
10
2
12
Some
We
Denition: Defense against the Dark Arts is
the science of Data.
How should it be collected?
How should it be summarized?
How should it be displayed?
How should it be interpreted?
Where are the pitfalls?
6
Jargon
Usual structure of data set.
Individuals, s
* Data step command:
Deleting observations (rows) from datasets;
- use the delete command coded as
data newds;
set oldds;
if fat < 0 then delete;
run;
- use a subsetting IF command
(http:/support.sas.com/documentation/cdl/en/lrdict/64316/HTML/defaul
t/vie
proc sgplot/ sgscatter
- standard graphs
- scatter/ series/ highlow/ band/ refline/ reg/
xaxis/ yaxis statements
= use the /group =var option on many statements
to differentiate
among groups using different colors/symbols
proc sort - sort ds by variables.
* Adding observatios to a dataset
In some cases you want to ADD observations to a dataset.
For example, we used Proc Reg to find the relationship
between calories and grams of fat, and want to make predictions
at various fat levels.
(1) Create the dataset
Creating output in nice formats
- default output from Procs goes to your screen in
html format
- use ods pdf file=xxxx; . ods pdf close; to send
everything to single pdf file
- use ods rtf file=xxxx; . ods rtf close; to send
output to rtf file for word pr
The main point of this example is that the type of
"atheoretical"
search for patterns that we are sometimes warned
against in graduate
school can save us from the humiliation of having to
retract
conclusions we might ultimately make on the basis of
contam
It is sometimes thought that correlation does not prove
causation but
"causal modeling" does. Despite the admonitions of
experts in this
field, researchers sometimes use goodness-of-fit
indices to hunt
through thickets of competing models and settle on a
An Important Distinction: Observational Studies versus Randomized
Experiments
Observation Versus Experiment
An observational study observes individuals and measures variables of interest but
does not attempt to influence the responses.
An experiment, on t
Regression
1 of 3
http:/members.shaw.ca/scottpai/Regression1.html
1. Given a dataset (X1, Y1), (X2, Y2), , (Xn, Yn). To study the relationship between X and Y, we
begin with a scatterplot.
2. If the scatter diagram is football-shaped, it suggests a linear
Residuals can be used to check to see how well the regre.
1 of 6
http:/members.shaw.ca/scottpai/Producing_Data.html
The following lecture notes are modified from Mr. Insleys class notes.
Producing Data: Sampling and Experiments
The two sources of data for
Ethan Frome
1 of 3
http:/members.shaw.ca/scpai/s201_sample_post.html
Statistics 201
Sample Midterm Exam I October 5, 2007
Instructions:
Closed books/notes examination, except that you may use a one page of notes written on both sides.
Also Checkout Exam F
Supplementary Teaching Material provided by Mr
1 of 3
http:/members.shaw.ca/scott.pai/Histogram.html
Supplementary Teaching Material provided by Mr. Robin Insley
-Percentages of Persons 65 Years old or Older in large urban places in 2000
-Case Percent 65+
When estimating percentages, it is the absolute size of .
1 of 4
http:/members.shaw.ca/scot_pai/data1.htm
Example:
The Census Bureau of US is planning to take a simple random sample amounting to 1/10 of 1% of
the population in each state in order to estim
When estimating percentages, it is the absolute size of the sample
which determines accuracy, not the size relative to the population.
This is true if the sample is only a small part of the population,
which is the usual case.
Example:
The Census Bureau o
Producing Data: Sampling and Experiments
The two sources of data for analysis and statistical inference come from:
i)
Experimentally generated data: An experiment is set up and the values of an
explanatory variable are changed by the experimenter in a sys
Review for the Midterm
What calculations do you need to know about:
Making normal approximation to histogram.
Making a normal approximation to compute a probability in Binomial trials.
Computing a regression prediction.
Computing the residual standard
Chapter 16: Inference about a Population Mean.
Thanks to Mr. Robin Insley
In chapters 14 where a confidence interval for was constructed and in
chapter15
where we did a test of significance on we needed the distribution of
the one- sample z statistic, z =
STAT 201
Midterm Examination
Richard Lockhart
Instructions:
21 October 2004
1. This is a closed book exam.
2. You may use a calculator (with no wireless communications ability).
3. You may bring one sheet of notes.
4. You may also bring the tear out sheet
Statistics 201
Sample Final Exam April 13, 2014 (Sunday, 3:30pm - 6:30pm)
Instructions:
1. Closed books/notes examination, except that you may use a one page of notes written on both sides. Time
allowed: 3 hours.
2. Leave your answers in the space provide
STAT 201 Quiz 3 solutions
May 30, 2003
Student #:
Name:
I randomly select (with replacement) two students from the Stat 201 class. Im interested in
whether each shares my birthday.
Assume each random selection is just like randomly selecting a day out of
STAT 201 Quiz 5 Solutions
June 13, 2003
Student #:
Name:
Show work for all calculations. You need NOT use a calculator.
e.g. You may leave
2
2.06 0.4
5
as your nal answer.
A university is contemplating switching from the semester system to the quarter sy
STAT 201 Quiz 8 Solutions
July 11, 2003
Name:
Student #:
Show work for all calculations. You need NOT use a calculator.
e.g. You may leave
2
0.4/10 + .25/8
5 2.06
as your nal answer.
Below are data on chest diameter (in) and weight (lb) for 19 randomly s
Chapter 1: Picturing Distributions with Graphs (did not do stem-plots)
Chapter 2: Describing Distributions with Numbers (note: do not need
to compute variance or standard deviation by hand, but DO need to
interpret)
Chapter 4: Scatter-plots and correla
Statistics 201
SAMPLE Mid-term 1
DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO!
Name:
_
Student Number:
_
Signature:
_
Instructions:
1. Do not panic. It rarely helps.
2. Read all questions carefully.
3. You do not need to provide an explanation for mu
12.14
(a) This is legitimate because the probabilities are all greater than 0 and sum to 1.
(b) The event cfw_ < 4 is the event that somebody eats dinner at home with their family 3
or fewer days per week.
< 4 = 0.05 + 0.00 + 0.07 + 0.08 = 0.20
(c ) This
Q1:
a)
is the mean from a sample of size n from a population, and there are multiple
s
that are taken. The mean of all the
s is always equal to the mean of the population, ,
so there is no tendency to overestimate or underestimate the parameter . Therefor
Q9:
a) Distribution of the data:
Summary Statistics
Mean
Std Dev
Std Err Mean
Upper 95% Mean
Lower 95% Mean
N
-4.606897
5.4027064
1.0032574
-2.551817
-6.661976
29
What makes me doubt the validity of the
confidence interval is the fact that the
histogram d
Q5:
It is incorrect because the 95% confidence interval means that 95% of the observed
confidence intervals will contain the true value of the population mean. So, across many
repeated samples, 95% of them will contain the true population mean value.
Q4:
a) Primary language does not necessarily mean the language of the birth country. Primary
language is just the language spoken the most by an individual and may have nothing to
do with the birth countrys official language.
b) Correlation is a number be
Q8:
a) The individual in the study is a teenager.
b) The explanatory variable is marijuana use. The response variable is the gray matter
density in the brain.
c) This is an observational study because the researchers did not actually manipulate the
teenag