BADM 572 Module 3 Study Session
31 March 2019
Housekeeping
 Our study sessions will be held once per week and will focus on the course
objectives for that module
 Yes, I am recording this session and will post it in Workplace along with a PDF of this
presentation
 Our study sessions are in support of (not replacement for) the Coursera content, live
sessions, Compass content and Professor office hours
– Critical that you base your studies on the official materials
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Our Agenda
 Upon successful completion of this module, you will be able to:
– Compare types of statistical studies.
– Compare types of sampling.
– Explain sampling and sampling distributions using the Central Limit Theorem.
 Develop your answers to the following guiding questions while watching
lectures and working on assignments throughout the module.
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What is an independent variable?
What is the response variable?
What is non-probability sampling technique?
What is a probability sampling technique?
What is the Central Limit Theorem?
What is the distribution of Sample Means?
What is difference between standard deviation and standard error?
Statistics vs Probability
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Producing Data
 30 Resources to Find the Data You Need
– https://flowingdata.com/2009/10/01/30-resources-to-find-the-data-you-need/
 Big Data: 33 Brilliant And Free Data Sources Anyone Can Use
– https://www.forbes.com/sites/bernardmarr/2016/02/12/big-data-35-brilliant-and-free-datasources-for-2016/#659d3f8fb54d
 19 Free Public Data Sets for Your First Data Science Project
– https://www.springboard.com/blog/free-public-data-sets-data-science-project/
 Statistical Methods & Data Sources
– https://guides.emich.edu/data/free-data
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Initiating a study
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Type of study
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Type of study
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Sampling
Probability
• All elements are
considered and each
has equal change of
being selected
• Population is divided
into subpopulations/stratum &
subjects selected
randomly
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Non-Probability
• Every nth element
chosen
• Based on ease of
accessibility
• Deliberately select
sample to confirm to
some criteria
Simple
Random
Systematic
Convenience
Judgmental/
Purposive
Stratified
Cluster
Quota
Snowball
• Population divided
into clusters, random
sample of clusters is
selected from a
simple random
design
• Relevant
characteristics are
used to segregate the
sample to improve its
representativeness
• Referred by current
sample elements
Sampling
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Central Limit Theorem and Sampling Means
The Central Limit Theorem (CLT) is a statistical theory states that given a
sufficiently large sample size from a population with a finite level of variance,
the mean of all samples from the same population will be approximately equal
to the mean of the population AND they will conform to a normal distribution.
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Central Limit Theorem In Practice
http://onlinestatbook.com/stat_sim/sampling_dist/
http://www.ltcconline.net/greenl/java/Statistics/clt/cltsimulation.html
http://195.134.76.37/applets/AppletCentralLimit/Appl_CentralLimit2.html
http://mfviz.com/central-limit/
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Central Limit Theorem In Practice: Skewed Left
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Central Limit Theorem In Practice: Uniform
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Central Limit Theorem In Practice: Bimodal
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Central Limit Theorem In Practice: Multimodel
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What is difference between standard deviation and standard error?
Standard Deviation: a measure of how spread out the data is from the mean
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Be careful with the language you use for Standard Deviations
• Standard Deviation
is a distance from
the mean
• Can be generically
described as “1
standard deviation”
• Z score is the
number of standard
deviations
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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What is difference between standard deviation and standard error?
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Standard Deviation And Standard Error In Practice
Let’s practice
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Sample size vs # of samples
Sample size 25 and
100 samples
# simulation
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2
3
4
5
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avg
52.2523
51.9193
51.9072
51.9591
51.9157
std error
2.0188
2.0277
2.0295
2.0721
2.0274
Sample size 25 and
1,000 samples
# simulation
1
2
3
4
5
avg
51.9723
51.9704
51.9722
51.9760
51.9749
std error
2.0890
2.0902
2.0890
2.0915
2.0901
Sample size 100 and
1,000 samples
# simulation
1
2
3
4
5
avg
51.9556
51.9531
51.9576
51.9570
51.9571
std error
1.5371
1.5403
1.5375
1.5370
1.5371
Thank you for attending
Questions?
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