Transcript Class 11 - March 24, 2010 - Quanitative Research I

EDIT 6900: Research Methods in
Instructional Technology
Lloyd Rieber
Instructor
Eunjung Oh
Graduate Assistant
UGA, Instructional Technology
Spring, 2008
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Two Topics for Today
• Introduction to Quantitative Research
Methods (just beginning)
• Overview of a class activity on how to
compute the mean, standard deviation,
and z scores.
Not This Week
Informal Activity
SDC
Systematic Data Collection
• An informal, (hopefully) enjoyable activity
designed to give you first-hand
experience collecting research data
• Your Task: Go and research something of
interest to you!
• Report on it informally in writing
• Give 5 minute oral report
• 10%, Due: April 9
Remaining Course Calendar
March 26
Quantitative Research (con’t)
April 2
Quantitative Research
April 9
Preparing a Research Report
SDC Reports (in class)
Finish SDC Reports (if needed)
Research Project Presentations?
April 16
April 23
Research Project Presentations
Notes About the Next RDA
Notes About the Next RDA
Course Project:
Will you do this individually or
with a partner?
Date to
decide
by: update
February
To declare
your
intention,
your5class
profile and write the name of your partner or
the word “individual” in the field titled
“Project Team.”
EDIT 6900 Research in Instructional Technology
Part IV. Quantitative Research
Methodologies
Chapters 9-11
Dr. Lloyd Rieber
The University of Georgia
Department of Educational Psychology
& Instructional Technology
Athens, Georgia USA
Quick Polls on this Chapter
Descriptive Research
 Examines situation as it is.
 Does not involve changing or modifying situation under
investigation.
 Not used to determine cause-and-effect relationships.
Surveying a Population: the
United States Census
Excerpts From Ruling on Planned
Use of Statistical Sampling in 2000
Census
Reading section 141(a) and section 195 together,
and considering the plain text, legislative history
and other tools of statutory construction, this
court finds that the use of statistical sampling to
determine the population for purposes of the
apportionment of representatives in Congress
among the states violates the Census Act. . . .
Two Important Sets of
Descriptive Statistics
• Measures of Central Tendency
• Measures of variability
The Normal Distribution
Cool simulation of a classic phenomenon
resulting in a normal curve
– http://www.ms.uky.edu/~mai/java/stat/GaltonMachine.html
Measures of Central Tendency
• Mean
– The average of a set of numbers.
• Median
– Given a set of number arranged in descending
order, the median is the number at the midpoint.
• Mode
– Given a set of numbers, the mode is the number
with the greatest frequency.
• Given a normal distribution, these are all the
same number.
How to measure variability?
• Method 1: Compute the difference
between the highest and lowest score
– OK, but this only takes into account 2
scores!
• Method 2:
• Method 3:
How to measure variability?
• Method 1: Compute the difference
between the highest and lowest score
– OK, but this only takes into account 2
scores!
• Method 2: Compute the difference
between each score and group average
– OK, these are called deviation scores.
– Great! Let’s take the average of them.
– Oops! The answer is always 0!
• Method 3
How to measure variability?
• Method 1: Compute the difference between
the highest and lowest score
– OK, but this only takes into account 2 scores!
• Method 2: Compute the difference between
each score and group average
– OK, these are called deviation scores.
– Great! Let’s take the average of them.
– Oops! The answer is always 0!
• Method 3: Compute the standard deviation
– Pretty much still the average of these numbers,
but you square the difference scores first, then
take the square root. Pretty clever!
Standard Deviation
67 Years Since the Last .400 Hitter:
Baseball and the Importance of
Variance
The major league batting average
has always been around .260.
z Scores
• Your friend tells you he received a 95 on
a recent math exam. Are you
impressed?
Calculating z Scores


Using the mean and standard deviation to calculate z
(standard) scores
A standard score shows how far an individual’s
performance is from the mean in standard deviation
units.
Class Activity
Learning How to Compute the
Mean, Standard Deviation, and z
Scores of a Data Set
Did you say mathematics?
Your Task
(This has already been emailed to you.)
1. Finish watching my pre-recorded
presentation introducing quantitative
research methods first.
2. Launch Excel and create a spreadsheet.
3. Compute the mean, standard deviation, and
z scores of the data set emailed to you.
Follow my video tutorial.
4. Email your spreadsheet to me as an
attachment. (You do not have to finish this
evening, but I expect most will.)
This is meant as a class activity.
It is not a graded activity.
If you get stuck and become
totally frustrated, stop and send
me what you have.
To do list
• Follow the Course Learning Plan!