Quantitative Research Methodologies
Quantitative Research Methodologies
Quantitative Research Methodologies
CORRELATIONAL RESEARCH
EXPLANOTARY STUDIES
Researchers often investigate a number of variables they believe are related to a more complex variable. Unrelated variables dropped from further consideration Most researchers most probably trying to gain some ideas about cause and effect However it does not establish cause and effect
PREDICTION STUDIES
Predict a score on one variable if a score on the other variable is known Determine the predictive validity of measuring instruments Predictor Variable; variable that is used to make the prediction Criterion Variable; variable about which the prediction is made
2. The Coefficient of Multiple Correlation Symbolized by R; indicates the strength of the correlation between the combination of the predictor variables and the criterion variables. multiple correlation.jpg The higher R is, the more reliable a prediction will be
5. Factor Analysis
Technique that allows a researcher to determine if many variables can be described by a few factors.
2. Sample
Should be selected carefully, and if possible, randomly. Not less than 30.
3. Instruments
Most correlational studies involve the administration of some types of instruments (tests, questionnaire, and so on).
5. Data Collection
Data on both variables will usually be collected in a short time. Instruments used are administered in a single session or two sessions
1. Subject Characteristics
Individuals or groups have two or more characteristics; might be a cause of variation in the other two variables.
2. Location Location is different for different subject One location may be more comfortable compared to others 3. Instrumentation Instrument decay; care must be taken to ensure the observers dont become tired, bored or inattentive Data collector characteristics; different gender, age or ethnicity may affect specific response
4. Testing
Experience of responding to the first instrument may influence subject responses to the second instrument
5. Mortality
Loss of subjects may make a relationship more (or less) likely in the remaining data
1. Subject Characteristics
Four of many possible characteristics a. Severity of disability b. Socioeconomic level of parents c. Physical strength and coordination d. Physical appearance
2. Mortality
Loss of subjects can be expected to reduce magnitude of correlation
3. Location
Threats could be controlled by independently assessing the job-site environments.
4. Instrumentation
Instrument decay; observations should scheduled Data collector characteristics; interaction of data collectors and supervisors is a necessary parts Data collector bias; observers should have no knowledge of job ratings