Experiments

Question 1

What is the purpose of experiments?

Answer 1

To examine and test causal relationships or ceteris paribus relationships

Question 2

What are the rules of causality?

Answer 2

• To establish that variable X causes Y, all there conditions must be met:
• 1. Both X (cause) and Y (effect) should covary
• 2. X should precede Y. There must be a time sequence in which the two occur.
• 3. No other factor should possibly cause the change in the outcome Y. Other variables that might covary with Y must be controlled for

Question 3

What kinds of variables are there in experiments?

Answer 3

• Independent
• Dependent
• Confounding variable
• Extraneous variable

Question 4

What are independent variables?

Answer 4

• X

- Cause

Question 5

What are dependent variables?

Answer 5

• Y

- Effect

Question 6

What are confounding variables?

Answer 6

• When there is an alternative explanation beyond the experiment variables for any observed difference in the dependent variable
• Effects the DV
• DOES effect

Question 7

What are extraneous variables/

Answer 7

• Variables that naturally exist in the environment that may have some systematic effect on the V
• Could affect the DV but has been controlled for so it doesn’t
• MAY effect

Question 8

What are the two essential aspects of experiments?

Answer 8

• 1. Manipulation of the independent variables
     - The changes in X cannot occur naturally, they have to be deliberalty created, manipulated or arranged by the experimenter
• 2. Control of the extraneous variables
     - The method can only be used when subjects and conditions to be studies can be practically and ethically manipulated by the researcher

Question 9

What is the method to conducting experiments?

Answer 9

• Identify the causal factors
• Plan and Administer the manipulations
• Plan and apply controls
• Observe and Measure the DV

Question 10

What are treatments in experimentation?

Answer 10

• Manipulations of the IV are also known as treatments which are administered to the experimental groups whereas control groups do not receive these treatments

Question 11

What are the ways in which the IV can be manipulated?

Answer 11

• Presence vs Absence technique
• Amount technique
• Type technique

Question 12

How are controls planned and applied in the experimentation method?

Answer 12

• Proper sampling techniques
• Standardisation of conditions
• Controlling EVs and CEs

Question 13

How can EVs and CEs be controlled for?

Answer 13

• Confounding effects and extraneous variables can be minimised through good sampling
• Randomisation
• Matching groups

Question 14

What is randomisation in experimentation?

Answer 14

• For controlling for the EVs and CEs
• Involves randomly assigning subjects to experimental and control groups
• Doing so distributes the effects of counfounding variables across groups equally
• Any errors caused by say age or gender are now more or less similar across groups

Question 15

What are matching groups in experimentation?

Answer 15

• For controlling for the EVs and CEs
• More precise strategy
• On the basis of confounding variables
• e.g. the effects of gender and age can be distribute across groups
• The risk is that we may fail to match some critical factors across groups

Question 16

What is the treatment effect?

Answer 16

In observing and measuring the DV, the difference between pre-testing and post-testing

Question 17

What are the types of experimental design?

Answer 17

• Two randomised groups design (classic design)
• Two matched groups design
• Two within-subjects groups design
• Multiple Groups designs
• Facotrial designs

Question 18

What is the two randomised groups experimental design (classic design)?

Answer 18

Random assignment of participants are made to the experimental and control groups

Question 19

What is the two matched groups experimental design?

Answer 19

Participants in the experimental and control groups are matched with one another in terms of potential EVs

Question 20

What is the two within-subjects group experimentals design?

Answer 20

Participants in the experimental and ctonrol groups are the same people, measures before and after the treatment - the ultimate in matching

Question 21

What is the multiple groups experimental design?

Answer 21

IV has more than 2 conditions; participants can be randomly assigned, matched or repeated across the conditions

Question 22

What is the factorial experimental design?

Answer 22

More than one IV is investigated, allows experiments to test a more complex causal hypothesis as DVs can have multiple causes; allows exploration of interactions effects of IVs too

Question 23

What are the two types of experiments?

Answer 23

• Laboratory
  
  • Contrived but standardised environment
  • When manipulations and controls are introduced to establish cause-effect relationship in an artificial setting
• Field
  
  • Conducted in a natural setting, often for a longer period of time
  • Not possible to control for all extraneous variables in the field because it may not be possible to assign subjects to groups or match them

Question 24

How can the internal validity of an experiment be measured?

Answer 24

• Did the experiment measure what is set out to do
• The ability of an experiment to establish whether the experimental treatment (IV) was the sole cause of changes in a DV
• Experiment is invalid if there are rival hypotheses or alternative explanations for the results

Question 25

How can the external validity of an experiment be measured?

Answer 25

- Can the findings be applied to other situations outside the experimental situation - The extent to which the results found are generalisable to actual field or organisational settings

Question 26

What is true of the validity of the different types of experiments?

Answer 26

- Lab experiments have high internal validity but low external validity compared to field experiments - To ensure both types, some researches first test causal relationship in a laboratory setting, and then examine whether such relationship are generalisable to the field setting

Question 27

What threats to experimental validity are there?

Answer 27

* History effects * Maturation Effects * Testing Effect * Instrumentation Effect * Selection Bias Effects * Demand Effects * Hawthorne Effect * Morality or Attrition

Question 28

What is the history effect threat to experimental validity?

Answer 28

- Specific events that occur while the experiment is in progress that could impact on the DV, but are beyond the control of the experiementer - e.g. a natural disaster or an economic downturn occurs; new laws are passed; the company downsizes

Question 29

What is the maturation effect threat to experimental validity?

Answer 29

- The passage of time over the course of the experiment can influence the DV - Subjects can get tired, gain experience, get bored, grow older and these processes can affect the DV

Question 30

What is the testing effect threat to experimental validity?

Answer 30

- Mere exposure to the pre-test may influence results of the post-test - Participants become sensitised to the post-test

Question 31

What is the instrumentation effect threat to experimental validity?

Answer 31

Changes in the measuring instruments between pre-test and post-test can also influence the DV

Question 32

What is the selection bias effect threat to experimental validity?

Answer 32

- Improper selection of subjects for the experimental or control groups - Subjects in experimental and control groups can not be matched

Question 33

What is the demand effect threat to experimental validity?

Answer 33

- When participants pick up cues during an experiments and modify their behaviours - Some may try to please the experimenter and give her they thing she wants/expects - Others might mess it up for the experimenter

Question 34

What is the Hawthorne effect threat to experimental validity?

Answer 34

The act of observation causes people to act differently from normal

Question 35

What is the morality or attrition threat to experimental validity?

Answer 35

- Composition of the groups can change when participants drop-out or withdraw - This makes it difficult to compare experimental and control group