Download - Descriptive study and descriptive statistics
Educational Research: Descriptive study and descriptive statistics
ELT-718Asst. Prof. Dr. Hasan BEDİR
ÖĞRETMENLER GÜNÜSEVGİLİ MESLEKTAŞLARIM
ÖĞRETMENLER GÜNÜNÜZÜ EN İÇTEN DİLEKLERLE KUTLAR BAŞARILAR DİLERİM
ONA’DA BİR ZAMANLAR BOŞVER MEMLEKETİ SEN Mİ
KURTARACAKSIN DEMİŞLERDİ
Types of researchResearch Type Purpose Control Time Frame Code Words Example
Nonexperimental (Descriptive)
Describe the characteristics of an existing phenomenon
None or Low
Current “describe” “interview” “review literature
A survey to determine gender differences in language learning
Nonexperimental (Historical)
Relate events that have occurred in the past to current events.
None to Low
Past “past” “describe”
The historical influence of innovations in the approaches and methods improved in language teaching
Nonexperimental (Correlational)
Examine the relationships between variables.
Low to Medium
Current or Past (correlation) future (prediction)
“relationship”“related to”“associated with”“predicts”
What is he relationship between reading and writing achievements of ELT students satisfaction?
Research Type Purpose Control Time Frame Code Words
Example
Experimental To test for a true cause/effect relationship
High Current “Function of”“Cause of”“Comparison between”“Effects of”
The effects of metacognitive strategies in reading comprehension ability of 7th grade primary school students
Quasi-Experimental
To test for causal relationships without having full control
Moderate to high
Current or Past
“Function of”“Cause of”“Comparison between”“Effects of”
The effects of faculties in the achievement of KPSS exam
WHAT METHOD TO USE WHEN?
Differences between groups?
CorrelationalHistorical research
Descriptive research
Are you studying
events that occurred in
the past?
Are you studying
events that primarily occur in
the present?
Are you studying the relationship
between variables (but not the effects
of one on the other)?
Are the participants preassigned to groups?
YesNo
NoYes
Experimental Research
YesNo
Yes
No
Yes
Non-experimental Research
True experimental
Quasi-experimental
Time to reconsider the question
No
Descriptive Research Designs Describes characteristics of existing
phenomena
Provides a broad picture
Serves as basis for other types of research
Studies primarily concerned with determining “what is.”
Dependent & independent variables are not used because there is no attempt to establish causality
Protection against bias
Examine characteristics of a single sample
Descriptive research provides answers to the questions of: Who What Where When How
We cannot answer the question Why? conclusively
Descriptive Researchtakes a “what is” approach
What is the best way to provide access to computer equipment in schools?
Do teachers hold favorable attitudes toward using computers in schools?
What have been the reactions of school administrators to technological innovations in teaching?
Descriptive Research Refers to the nature of the research
question The design of the research The way that data will be analyzed for the
topic that will be researchedThe type of research question will determine
whether descriptive research approach is appropriate to use.
Data Collection Methods
Surveys Interviews
Observations Portfolios
Descriptive Research4. Portfolios
Provide a descriptive measure of student work based on actual performance
Consist of learner-created products that reflect the processes of learning and development over time
Two aspects about surveys:
Survey Content Direct questioning Answering how,
what,and to what extent questions
Usually focus on what was done and what people plan to do in the future
Survey Administration Different data
collection methods Personal interviews Telephone interviews Self-administered
questionnaires (SAQs) Mixed-mode strategy
Surveys Two general formats
Questionnaire Interview
Some people think surveys are easier “Oh, I’ll just type it up and send them out.” Explicit design and thoughtful subject selection
are very important to the concept of control Always pilot test the instrument
Questionnaires & Interviews
Two Extremes Standardized Questionnaires or Structured
Interviews Unstructured (Not Questionnaires) or loose
unstructured interviews
Questionnaires
Two types of questions Base decision regarding structure on three
factors: verbal ability time outcomes
Question Wording and Content Clarity and precision Respondent's ability to provide requested
information Questions of personal or sensitive nature
are more easily released to questionnaires
Format
Appearance and layout of schedule Individuals must be able to follow
directions Follow schematic
questions should not be difficult to follow avoid boredom or being tired and refusing to
complete
Questionnaires May be Distributed by:
Hand
Online
Questionnaires (cont.) Important points to consider
Response/Nonresponse rates The % of recipients that actually completed the survey (or
didn’t return it) Structure
Overall look of survey Professional? Easy to understand?
Spacing of items or responses Type of items
Open-ended Closed response
Interviews may be conducted
Face-to-face
Over the Telephone
Interviews (cont.) Important points to consider
Structure of interview Very detailed questions and series of questions
Or open-ended? Script for interviewer to read
Characteristics of the interviewer Personal characteristics (ethnicity, age, sex) Communication skills/behavior Appearance
How are responses recorded? Paper Computer Audio or videotape
Observations Observer should NOT be a participant in
the setting Nonparticipant observation
Two types of settings Naturalistic Simulation
Observations (cont.) Important points
Variables to observe should be well-detailed Observable Measurable
Training of observers How was it done? How long did it take? How successful was it (i.e., how consistent are they)?
Interobserver reliability Make sure observers are consistent Recheck at various points throughout study
Observations (cont.) Important Points
How are observations recorded? Paper Computer Videotaped
Recording methods Continuous Interval
Whole Partial Momentary time sampling
Observations (cont.) Important Points
Data types1. Frequency (also called rate or tally)
How often a behavior occurs within a period of time
2. Duration How long a behavior lasts
3. Latency How long before the behavior occurs after a trigger
4. Intensity (also called severity) The amount or force of a behavior
Portfolios Provide a descriptive measure of student
work based on actual performance
Consist of learner-created products that reflect the processes of learning and development over time
Descriptive research: StatisticsTypes of Measurements
standardized achievement scores, classroom observation instruments, attitude scales, questionnaires, and interviews
Statistics Central Tendency (mean, median, mode)Measures of Variability (SD, variance, range)
Statistics...
A set of mathematical procedures for describing, synthesizing, analyzing, and interpreting quantitative data
…the selection of an appropriate statistical technique is determined by the research design, hypothesis, and the data collection technique
descriptive statistics...
…permit the researcher to describe many pieces of data with a few indices
statistics...
…indices calculated by the researcher for a sample drawn from a population
Types of descriptive statistics…
1. graphs
2. measures of central tendency
3. measures of variability
graphs...
…representations of data enabling the researcher to see what the distribution of scores look like
1. Graphs…
frequency polygon pie chart boxplot stem-and-leaf chart
42, 67, 73, 78, 82, 84, 86, 91, 94, 99
measures of central tendency...
…indices enabling the researcher to determine the typical or average score of a group of scores
2. Measures of central tendency…
mode median mean
mode...
…the score attained by more participants than any other score
median...
…the point in a distribution above and below which are 50% of the scores
mean...
…the arithmetic average of the scores
measures of variability...
…indices enabling the researcher to indicate how spread out a group of scores are
3. Measures of variability…
range quartile deviation variance standard deviation
range...
…the difference between the highest and lowest score in a distribution
quartile deviation...
…one half of the difference between the upper quartile (the 75%’ile) and the lower quartile (the 25%’ile) in a distribution
variance...
…a summary statistic indicating the degree of variability among participants for a given variable
standard deviation...
…the square root of variance providing an index of variability in the distribution of scores
Normal distributions of data(the normal curve)...
A bell-shaped distribution of scores having four identifiable properties…
…50% of the scores fall above the mean and 50% of the scores fall below the mean
…the mean, median, and mode are the same value
…most scores are near the mean and, the farther from the mean a score is, the fewer the number of participants who attained that score
…the same number, or percentage, of scores is between the mean and plus one standard deviation as is between the mean and minus one standard deviation
Non-normal distributions of data (skewed distributions)...
A non-bell-shaped distribution of scores where…
…mean < median < mode (a “negatively skewed distribution”)
…mean > median > mode (a “positively skewed distribution”)
measures of relative position...
…indices enabling the researcher to describe a participant’s performance compared to the performance of all other participants
4. Measures of relative position…
percentile ranks standard scores
percentile rank...
…indicates the percentage of scores that fall at or below a given score
standard score...
…a measure of relative position
Types of standard scores...
…z score
…T score
…stanines
z score...
…a statistic expressing how far a score is from the mean in terms of standard deviation units
T score...
…a transformed z score that voids negative numbers and decimals by multiplying the z score by 10 and adding 50
stanines...
…a standard score that divides a distribution into nine parts
…the presence of a correlation does not indicate a cause-effect relationship primarily because of the possibility of multiple confounding factors
Mini-Quiz…
True and false…
…the analysis of the data is as important as any other component of the research process
True
True and false…
…descriptive statistics are normally computed separately for each group in a research study
True
True and false…
…every instrument administered must always be scored accurately and consistently, using the same procedures and criteria
True
True and false…
…tentative scoring procedures must always be tried out beforehand by administering the instrument to the study participants
False
True and false…
…a computer should not be used to perform an analysis that a researcher has never completed by hand or, at least, studied extensively
True
True and false…
…the first step in data analysis is to describe, or summarize, the data using descriptive statistics
True
True and false…
…the number resulting from the computation of a measure of central tendency represents the typical score attained by a group of participants
True
True and false…
…the mean is the most precise, stable index of typical performance that is especially useful in situations in which there are extreme scores
False
True and false…
…standard scores are rarely used in research studies
True
True and false…
…if the extreme scores are at the upper, or higher end of the distribution, it is said to be positively skewed
True
True and false…
…the median of a set of scores corresponds to the 50% percentile
True
True and false…
…a z score expresses how far a score is from the mean in terms of standard deviation units
True
Fill in the blank…
…statistics which permit the researcher to describe many scores with a small number of indices
descriptive statistics
Fill in the blank…
…the values calculated for a sample drawn form a population
statistics
Fill in the blank…
…the score attained by more participants than any other score
mode
Fill in the blank…
…the point in a distribution above and below which are 50% of the scores
median
Fill in the blank…
…the arithmetic average of the scores
mean
Fill in the blank…
…the difference between the highest and lowest score in a distribution
range
Fill in the blank…
… the statistical procedures for describing, synthesizing, analyzing, and interpreting quantitative data
Descriptive statistics
Descriptive Research
The End