Experimental design, types, and sampling - psychology

What is independent groups design?

• Two separate groups of participants experience two different conditions of the experiment.

• All participants experience both conditions of the experiment - the experimental condition and the control condition.

• Participants are paired together based upon a variable/variables relevant to the experiment.

What is repeated measures design?

• Two separate groups of participants experience two different conditions of the experiment.

• All participants experience both conditions of the experiment - the experimental condition and the control condition.

• Participants are paired together based upon a variable/variables relevant to the experiment.

What is matched pairs design?

• Two separate groups of participants experience two different conditions of the experiment.

• All participants experience both conditions of the experiment - the experimental condition and the control condition.

• Participants are paired together based upon a variable/variables relevant to the experiment.

An attempt to control the effects of order in a repeated measures design: half the participants experience the conditions in one order, and the other half in the opposite order.

• Order effects

• Counterbalancing

• Control

Characteristics of individual participants (e.g. age, intelligence, etc.) that might influence the outcome of a study.

• Investigator bias

• Extraneous variables

• Investigator effects

• Participant variables

The entire group a researcher is interested in or the group about which the researcher wishes to draw conclusions. Usually researchers apply the conclusions to a wider population and then questions are asked about generalizability.

• Sampling units

• Target population

• Sampling frame

Bias is when certain groups may be over or under-represented within the sample selected

• True

• False

What is a random sample?

• All members of the target population have an equal chance of being selected.

• Every nth member of a target population is selected to be in a sample.

• The composition of the sample reflects the proportions of people in certain sub-groups (strata) within the target population / wider population.

• The researcher selects anyone who happens to be willing and available at the time of their study

• Involves participants selecting themselves to be a part of the sample.

What is a systematic sample?

• All members of the target population have an equal chance of being selected.

• Every nth member of a target population is selected to be in a sample.

• The composition of the sample reflects the proportions of people in certain sub-groups (strata) within the target population / wider population.

• The researcher selects anyone who happens to be willing and available at the time of their study

• Involves participants selecting themselves to be a part of the sample.

What is a stratified sample?

• All members of the target population have an equal chance of being selected.

• Every nth member of a target population is selected to be in a sample.

• The composition of the sample reflects the proportions of people in certain sub-groups (strata) within the target population / wider population.

• The researcher selects anyone who happens to be willing and available at the time of their study

• Involves participants selecting themselves to be a part of the sample.