Derived by singling out the individual factors influencing the independent variable
Conceptual model
Visual model using the sub-research questions, including theoretical concepts and control variables
Hypotheses
Formulated from the sub-research questions
Operational and conceptual definitions
Clearly define any concept touched on in the conceptual model
Indicators
Determined for each variable to measure the concepts
If the combination of indicators covers all aspects of a concept, it is said to be high in content validity
Unit of analysis
The level at which the research is performed, and which object are researched
The unit of analysis is derived from the research question
Sampling
Selecting some of the elements in a population to draw conclusions about the entire population
Population element
The subject on which the measurement is being taken
Representative samples are only a concern in quantitative studies rooted in a positivistic research approach. Qualitative studies rooted in interpretivism usually do not attempt to generalize their findings to a population
Census
A count of all the elements in a population
Reasons for sampling
Lower cost
Greater accuracy of results
Greater speed of data collection
Availability of population elements
Population
The group we want to say something about
Sampling frame
The group you can say something about
Sample
Your selection from the sampling frame
The advantages of sampling over census studies are less compelling when the population is small and the variability within the population high. Two conditions are appropriate for a census study: when the population is small and when the elements are quite different from each other
Characteristics of a correct sample
Accuracy: no systematic bias
Precision: values in the sample like values in the population
Accurate sample
One in which the under estimators and the over estimators are balanced among the members of the sample
Sampling error
The numerical descriptors that describe samples may be expected to differ from those that describe populations because of random fluctuations inherent in the sampling process
Sample types
Probability sampling
Non-probability sampling
Probability sampling
The members of a sample are selected on a probability basis or by another means, ensuring each population element has a known non-zero chance of selection
Simple random sampling
The simplest form of probability sampling where each population element has a known and equal chance of selection
Simple random sampling is often impractical as it requires a population list that is often not available, fails to use all the information about a population, and may be expensive to implement
Population parameters
Summary descriptors (mean, variance) of variables of interest in the population
Sample statistics
Descriptors of the relevant variables computed from sample data, used as estimators of population parameters
Systematic sampling
Every Kth element in the population is sampled, determined by dividing the sample size into the population size
Advantages of systematic sampling
Simplicity and flexibility
Stratified sampling
The population is divided into several mutually exclusive sub-populations or strata, and the sample is constrained to include elements from each segment
Reasons to choose stratified random sampling
To increase a sample's statistical efficiency
To provide adequate data for analyzing the various sub-populations
To enable different research methods and procedures to be used in different strata
Cluster sampling
The population consists of clusters of elements which are close to each other
Data types determine which statistical technique you can choose to analyze your data
Data types
Ratio
Interval
Ordinal
Nominal
Ratio
Order in numbers is important, intervals between numbers are fixed, meaningful zero point
Interval
Order in the numbers is important, interval between numbers is fixed
Ordinal
Order in the numbers is important, intervals between numbers are not fixed
Nominal
Numbers indicate categories, order is not meaningful