Research Flashcards
Step 1:
The process of reporting research begins with a purpose statement that identifies the variables being studied and the population to which they pertain.
There are three common types of variables in social research:
- Independent – Independent variables are those that are manipulated or selected by the researcher to cause, influence, or otherwise effect the outcome.
To identify the independent variable(s), ask, “What is the name of the theory or technique the researcher is using to cause change?” - Dependent – Dependent variables are those that are affected or changed as a result of the manipulation of the independent variable(s).
To determine the dependent variable, ask, “What is the researcher attempting to measure or test?” - Control – Control variables are possible confounding variables that the researcher attempts to hold constant so that their effects are canceled out or controlled for, such
as demographic or background characteristics of the subjects of a study.
To determine the control variable(s), ask, “What is the demographic or background information identified in the purpose statement?”
Step 2
The second step is to state the hypothesis. Pure experimental research is based on a null hypothesis — a statement that there is no true relationship existing between the independent and dependent variables.
Sample Null Hypothesis #1:
There is no significant difference between behavior therapy and physical therapy in reducing self-reported chronic lower back pain (CLBP), among adult males ages 40-60.
or
There is no significant difference in the reduction of self-reported chronic lower back pain (CLBP), among adult males ages 40-60, whether behavior therapy or physical therapy is used.
Sample Null Hypothesis #2:
There is no significant difference found between subjects’ scores on the communication scale with respect to their success in forming friendships as measured by a sociogram.
Four Types of Sampling Techniques
- Simple Random Sample – In a Simple Random Sample each item/subject in a sample is considered to have an equal, independent chance of being selected “into”
the sample. - Stratified Random Sample – In a Stratified Random Sample representative items/subjects are divided into parts (grades, ages, income, test scores, etc.). In
each part, each item/subject has an equal, independent chance of being selected “into” the sample. - Cluster Sample – In a Cluster Sample parts that go together are researched/studied together (neighborhood, class, etc.).
- Systematic Random Sample – In a Systematic Random Sample a systematic rule of selection or predictable interval is employed (every 3rd person, odd numbered,
etc.).
Sampling Error and Sampling Bias
1a. Sampling Error – occurs when subjects are not under the researcher’s control or when a discrepancy arises due to random sampling.
1b. Sampling Bias – is considered to be the researcher’s fault when it occurs because it involves a researcher’s selecting a non-representative sample for his/her own convenience or due to his/her own prejudices.
Threats to internal validity concern flaws in the design of the study. The following are types of threats to the internal validity of a study:
History Maturation Testing Statistical Regression Subject Attrition
Threats to external validity concern the extent to which the researcher can generalize findings to a larger population. Common threats to the external validity of a study include the following:
Hawthorne (placebo) Effect – occurs when the subjects’ knowledge that they are participants in a study alters or otherwise influences their usual responses.
Control: Have some sort of irrelevant treatment for the control group.
Threats to external validity concern the extent to which the researcher can generalize findings to a larger population. Common threats to the external validity of a study include the following:
Experimenter or Rosenthal Effect – occurs when the researcher/experimenter’s behavior or appearance affects the subject’s performance.
Control: Use more than one experimenter for interrater reliability.
Threats to external validity concern the extent to which the researcher can generalize findings to a larger population. Common threats to the external validity of a study include the following:
Halo Effect – occurs when the researcher/ experimenter allows his/her initial impressions of subjects to influence later ratings of subjects.
Control: The researcher recognizes and notes the bias
Types of Measurement Scales
A. Nominal or Categorical – is the lowest and least precise level of measurement as it simply classifies or sorts persons and/or objects into categories — names of categories — hence the term "nominal." Examples: yes/no male/female married/never married married/divorced/widowed Group 1/Group 2/Group 3
B. Ordinal (Order) – not only classifies subjects or their behaviors, but also ranks them in terms of the degree to which they possess a characteristic of interest. Intervals between ranks are not equal. Examples: BA/MA/Ph.D. 1st Place/2nd Place/3rd Place Freshman/Sophomore/Junior/Senior Chapter 1/Chapter 2/Chapter 3/Chapter 4
C. Interval (Equal) – has all the characteristics of both a nominal and ordinal scale, but, in addition, it is based upon predetermined equal intervals.
Examples: 1, 2, 3 or 3, 2, 1
-1, -2, -3 or -3, -2, -1
20 degrees, 40 degrees, 60 degrees;
-20 degrees, -40 degrees, -60 degrees
Note: Most of the tests used in educational research, such as achievement tests,
aptitude tests, and intelligence tests, represent interval scales. Interval
scales do not have a true zero point (which means they CAN HAVE
negative numbers).
D. Ratio – is the highest, most precise, level of measurement. A ratio scale has all of the advantages of the other types of scales and, in addition, it has a true zero point (NO negative numbers). Examples: 5 lbs., 10 lbs., 15 lbs. 10 inches, 12 inches, 14 inches 25 cents, 50 cents, 75 cents, $1.00
AB Design
is the simplest single-subject design. It includes one baseline phase (A) and one intervention phase (B).
ABAB Design
is designed to better control for outside events. The 2nd “A” stands for a second baseline phase (which would occur after some period of time AFTER the withdrawal or removal of the intervention). The 2nd “B” stands for the RE-introducing of the intervention. So, if you were to be asked to interpret what “ABA” represents, you would deduce that there has been an initial baseline established, an intervention has been introduced, and that the researcher has now withdrawn the intervention. After some period of time, another baseline will be established - thus the second “A.”
Quasi-experimental Research
Quasi-experimental Research – is widely used in the counseling field. Only the first of the two criteria listed above for experimental research is met since subjects are
usually not randomly assigned because the groups under study are already intact (classroom groups, etc.).
Types of Derived Scores
Grade Equivalent
denotes that average raw scores are assigned a grade-level value. We interpret a given score compared to other “x” graders: This subject performed at an average/below average/above average level.
Example: So, if a third (3rd) grader, Mary, scores a 4.5 on a reading test, theappropriate way to interpret/report the score is to say, “Mary scored above average in reading.”
Types of Derived Scores
Percentile Rank
indicates the percentage of scores that fall at or below a
given score.
Example: So, if John scored a 59 on a reading test and that score landed him at the PR of 45 (based on a graphing of the scores), the meaning is that 45% of the students who took the test earned scores of 59 or less.
Types of Derived Scores
Standard Scores
- z-score – is the most basic standard score and allows scores from different tests to be compared. The z-score has a mean of zero and a standard deviation (SD) of
one. - T-score – is widely used and has a mean of 50 and a standard deviation (SD) of 10.
- Stanines – (contraction of the two words “standard nine”)
divide the normal curve into nine parts,
NOT NINE EQUAL PARTS.
