Control Issues

Question 1

What are Between-subjects designs ?

Answer 1

An experimental design in which independent groups of participants take part in each condition

Question 2

What is meant by control ?

Answer 2

The act of reducing unwanted effects in an experiment by incorporating techniques that reduce them as much as possible

Question 3

What is the main problem that you will face in between-subject designs and how can you control it ?

Answer 3

Participant variable - to create equivalent groups

Solve this by random assignment of participants

Question 4

What is meant by within-subject design

Answer 4

An experimental design in which each participant takes part in all conditions of the independent variable

Question 5

What is the main problem you will face when conducting a within-subject design ?

Answer 5

Participating in one condition might affect behaviour in another condition (sequencing effects)

Question 6

When do we use between-group designs ?

Answer 6

1. When the IV is a subject variable (a variable that the researcher cannot manipulate)
2. When the experience gained in one level would make it impossible to participate in another level

Question 7

What are the advantages of using Within-group designs?

Answer 7

1. Need fewer people
2. No problem with equivalent groups
3. Reduces error variance, since you have no between-condition individual difference - so it gives more statistical power to find an effect if there is one

Question 8

What is meant by a factorial design ?

Answer 8

Research design that has more than one independent variable, with every level of one independent variable being combined with every level of every other independent variable

Question 9

Experimental designs are often called ______

Answer 9

True experiments

Question 10

What are subject variables ?

Answer 10

Things that the researcher cannot manipulate

Question 11

What are the advantages of a between group design ?

Answer 11

• No carry-over effects
• Shorter study sessions
• experiments are easy to set up

Question 12

What is the goal of random assignment

Answer 12

To take individual factors that could bias the study, and spread them out evenly throughout the different groups

Question 13

When would we use the matching method

Answer 13

When only a small number of participants are available and/or you can’t use random assignment

Question 14

What are the advantages of within-group designs ?

Answer 14

• need fewer people
• no problems with equivalent groups
• reduces error variance

Question 15

What are the problems when using within-group designs ?

Answer 15

• Order effects
• practice effects
• fatigue effects
• carryover effects

Question 16

What is meant by mixed designs and what is critically important when using this design ?

Answer 16

When you have both between and within- group designs

Control groups