Course Content

I. Introduction to the Research Process

II. Identification of the Research Problem

III. Development of the Research Question or Hypothesis

IV. Formulation of the Research Methods

V. Analysis and Interpretation of the Collected Data

VI. Writing the Research Report

The Scientific Method

1. Develop the problem

2. Develop a theoretical solution to the problem

3. Formulate the hypothesis or question

4. Formulate the research plan (methods)

5. Collect and analyze the data

6. Interpret the results and form conclusions

7. Refine the theory

Formulation of the Research Methods

A. Selecting the Appropriate Design

B. Selecting the Subjects

C. Selecting Measurement Methods & Techniques

D. Selecting Instrumentation

Formulation of the Research Methods

E. Developing Procedures & ProtocolF. Using a Pilot StudyG. Selecting the Appropriate Analysis

TechniquesH. Developing a Timeline & BudgetI. Collecting the Data

Sampling Procedures

Definitions

Population – group of things (people) having one or more common characteristics

Sample – representative subgroup of the larger populationUsed to estimate something about a population

(generalize)Must be similar to population on characteristic

being investigated

Representative

Sampling Methods

Probability Sampling Simple random sampling Stratified random

sampling Systematic sampling Cluster (area) sampling Multistage sampling

Non-Probability Sampling Deliberate (quota)

sampling Convenience sampling Purposive sampling

Simple Random Sampling

Equal probability Techniques

Fishbowl (with replacement & w/o replacement) Table of random numbers

Advantage Most representative group

Disadvantage Difficult to identify every member of a population

Stratified Random Sampling

Technique Divide population into various strata Randomly sample within each strata Sample from each strata should be proportional

Advantage Better in achieving representativeness on control

variable Disadvantage

Difficult to pick appropriate strata Difficult to ID every member in population

Systematic Sampling

Technique Use “system” to select sample (e.g., every 5th item in

alphabetized list, every 10th name in phone book) Advantage

Quick, efficient, saves time and energy Disadvantage

Not entirely bias free; each item does not have equal chance to be selected

System for selecting subjects may introduce systematic error Cannot generalize beyond pop actually sampled

Cluster (Area) Sampling

Randomly select groups (cluster) – all members of groups are subjects

Appropriate when you can’t obtain a list of the members of the

population have little knowledge of pop characteristics Pop is scattered over large geographic area

Cluster (Area) Sampling

Advantage More practical, less costly

Conclusions should be stated in terms of cluster (sample unit – school)

Sample size is # of clusters

Multistage Sampling

Stage 1 randomly sample clusters (schools)

Stage 2 randomly sample individuals from the schools

selected

Sampling Methods

Probability Sampling Simple random sampling Stratified random

sampling Systematic sampling Cluster (area) sampling Multistage sampling

Non-Probability Sampling Deliberate (quota)

sampling Convenience sampling Purposive sampling

Deliberate (Quota) Sampling

Similar to stratified random sampling Technique

Quotas set using some characteristic of the population thought to be relevant

Subjects selected non-randomly to meet quotas (usu. convenience sampling)

Disadvantage selection bias Cannot set quotas for all characteristics important to

study

Convenience Sampling

“Take them where you find them” - nonrandom Intact classes, volunteers, survey respondents

(low return), a typical group, a typical person Disadvantage: Selection bias Use post hoc analysis to show groups were

equal at the start

Sample Size

Critical factor is whether sample is representative Necessary sample size depends on population size Recommendations:

Use tables from books 30 per group Descriptive studies – 10-20% of population No more than 50% of population

Statistical power Attrition

Other Sampling Considerations

Random assignment Sampling of treatments (experimental research) Use post hoc analysis to show groups were equal at

the start Since random sampling is often impossible, sample

must be selected on some theoretical basis Be careful with generalizations

When Selecting Subjects …

Are subjects with special characteristics necessary for your research? (age, gender, trained/untrained, expert/novice, size, etc.)

Can you obtain the necessary permission and cooperation from the subjects?

Can you find enough subjects?

Interaction among selection of subjects, treatments, and measures is essential for experimental studies.

Reporting Subjects

State how many subjects were selected Describe how the subjects were selected Discuss whether any subjects were lost during

the study and why Explain why the subjects were selected Describe subject characteristics that are

pertinent to study – be very specific Identify procedures taken to protect the subjects