Week 2 Research Design: Basic Principles

Question 1

What is the purpose of research design?

Answer 1

To provide answers to research questions in the most accurate, valid, objective and economical way possible. To make inferences to the population

Question 2

What ways can you control variance?

Answer 2

Maximize systematic variance, Control extraneous systematic variance and minimize error variance

Question 3

How to maximize systematic variance?

Answer 3

Research be designed and conducted so the experimental conditions (IV & DV) are as different as possible.
Control extraneous variables.

Question 4

Define systematic variance and unsystematic variance?

Answer 4

Systematic variance: treatment effects

Unsystematic variance: error variance

Question 5

What are the four ways to control extraneous variables?

Answer 5

• Eliminate the variable (cannot generalize)
• Randomization (only method to control all extraneous variables, experimental groups statistically equal in all ways)
• Build into design
• Match participants (good for repeated measures design)

Question 6

How to minimize error variance?

Answer 6

Control conditions and use reliable measures

Question 7

What is error variance?

Answer 7

The variability of measures due to random fluctuations (individual differences & errors of measurement)

Question 8

Name the non-interpretable designs.

Answer 8

• Single-group, post test only design
• One-group, pretest-post test design
• Post test-only design with non-equivalent groups
  These can help to generate hypotheses

Question 9

What is a single-group post test only design?

Answer 9

One group with a treatment then observation
G1: X O
No pretest obs
no control group to compare

Question 10

What is the one-group pretest-post test design?

Answer 10

Pretest obs, treatment, post test obs
G1 O1 X O2
does not control for confounding variables

Question 11

What are confounding variables?

Answer 11

Extraneous variable that interferes with IV and DV:

• history
• maturation
• measurement
• statistical regression
• selection
• instrumentation
• mortality or attribution

Question 12

What is statistical regression?

Answer 12

Lowering of extremely high or raising of extremely low scores due to mean (retesting situation)

Question 13

What is the post test only design with non-equivalent groups?

Answer 13

Two groups one w/ treatment one w/o then obs
G1 X O
G2 O
no randomization, therefore no equivalence before treatment

Question 14

What are the criteria of a research design?

Answer 14

Answer research Q?

Control extraneous variables?

Question 15

What is external validity?

Answer 15

Extent to which the results can be generalized to other subjects, conditions, times, places (population)
Is of more interest in applied research than basic research

Question 16

What is internal validity?

Answer 16

Extent to which researcher can accurately state that the IV produced an observed effect.
When all effect (as measured by DV) is due to the IV, then internal validity has been achieved.
Must control confounding variables to achieve.

Question 17

What are the characteristics of experiments?

Answer 17

• manipulation of one or more factors (IV/s) to measure effects (DV) the manipulation has on behaviour
• internal validity
• reliability (replicatable experiment and results)
• sensitivity (power)
• external validity

Question 18

Research design steps?

Answer 18

• Problem statement
• theoretical constructs
• IV and DV
• Hypotheses and stat hyp
• population
• # of subjects required
• define procedure
• anticipate threats to validity
• create controls
• determination of stat analysis to be performed

Question 19

What are subject artifacts?

Answer 19

• Demand characteristics

Altruism, obedience and evaluation apprehension

Question 20

What are experimenter artifacts?

Answer 20

• Noninteractional (observer, interpreter and intentional effects)
• Interactional (biosocial and psychosocial effects)
• Situational (environmental) effects
• effects of researcher’s expectancy (E may behave differently to get + results)

Question 21

What are the controls to reduce threats to validity?

Answer 21

• general control procedures
• control over S/E effects
• control of selection and assignment (randomization)
• Control through specific experimental design (B, W, M)

Question 22

Procedures to control demand characteristics and experimenter effects?

Answer 22

• Deception (needs debriefing)
• Placebo controls
• Double blind procedure
• limit E communication with S’s
• Automate
• Experimental setting and procedures low key and nonthreatening.