EXPERIMENTAL RESEARCH METHODS: SAMPLING AND

ETHICSMs. Carmelitano

Good Psychological Studies

In order to conduct a successful study, researchers need to have a plan, people to participate in a study, a method to collect and analyze data.

Experimental Method 1) Develop an Aim:

The Aim is the purpose of the study, what will you study

2) Plan a Procedure The step-by-step process that the researcher will

follow to carry out the study 3) The Findings

How the researcher interprets the data that is collected

Creating the experiment

First you need participants! People who take place in a study The Target Population is the specific group the

researcher will investigate IE: Children from single family houses, people

who have been abused, twins, etc It is not possible to test the entire target

population, so a sample is needed A good sample is a representative sample, this

means that it represents the overall population

Finding Participants

Opportunity Sampling: a sample of whoever happens to be there and agrees to participate Gathered through advertising, usually

universities Can lead to biased results because hard to

generalize to larger population Self-Selected Sampling: a sample made

up of volunteers However, rarely represent larger general

population

Opportunity Sampling:

Mall Survey:

Want a free gift card?? Stop and take a survey!

Self-Selected:

Need help quitting smoking?

Come to town hall on Monday

June 11th to be part of a new medication trial that

will help you quit!

Finding Participants

• Snowball Sampling: When participants of a study recruit other participants from friends and family May bias the findings if all participants share a common

set of traits Random Sampling: One in which every

member of the target population has an equal chance of being selected Most desirable because most likely to contain all the

characteristics of the population Findings can be generalized to the larger population However, some groups may be over represented

Snowball Sampling

Random Sampling

Finding Participants

Stratified Sampling: draws random samples from each subpopulation within the target population Example: If a researcher does a study in a

school that has 20% Indian population, then for a sample containing 20 students, 6 chosen for the study would be Indian.

Stratified Sampling

Activity

For each of the following scenarios, what sampling technique was used and why? 1. A researcher at the mall asks teenagers

who pass her booth to fill out a survey

2. A researcher wants to know what the effect of video games has on a child's behavior in a certain school. They find the percent of African, Caucasian, and Hispanic Americans in a school. They then carefully select participants so that their sample contains the same percentages.

Activity

3. A researcher wants to test the effect reading has on students. They go to a specific school, and give each student a number. At random, they pull numbers out of a hat. Those students are tested.

4. A researcher wants to test hypnosis as a way to help people quit smoking. They put an advertisement in a paper, and wait for the phone calls.

Activity

5. A researcher wants to conduct a study looking at the long term affects of spousal abuse on women. They go to a support group, and ask for participants. They then ask the women they have selected to recruit other women in the support group to also be apart of the study.

Ethics in research

Participants in a study should always be treated in an ethical manner

Psychologists agree on certain ethical standards to not harm human beings 1. Informed Consent – Participants must be

informed about the nature of the study 2. Deception: Slight deception may be used if

necessary for the study, but at the end of the study full disclosure should be made

3. Debriefing – at the end of the study, the true aim and results should be disclosed to participants.

4. Withdrawal from a study – At the beginning of the study, participants should be told that they have the right to withdraw at any point

5. Confidentiality – All information obtained must be confidential

6. Protection from physical or mental harm – no harm is to be done to participants. You should not humiliate participants or force them to reveal private information

ACTIVITY: Is this ethical? How could you make it ethical?