basic laboratory experiments - reading chapter 9

Question 1

Repeated measures design

Answer 1

same ppt + all conditions – correlated t – test
Ppts:
• Condition 1
• Condition 2

Question 2

Independent groups design

Answer 2

different ppt + different condition – unrelated t-test
Ppts:
• Group 1
- condition A 1st
- condition B 2nd
- Group 2
- condition B 1st
- condition A 2nd

Question 3

Characteristics of true or randomised experiment – aspects of experience

Answer 3

• Experimental manipulation
• Standardised procedures
• Random assignment

Question 4

• Experimental manipulation

Answer 4

• manipulation of IV to test effects on DV
• condition with lower level of IV = control group e.g. lower alchohol
• condition with higher IV = experimental condition
• experimental control condition should be almost identical aside from IV

Question 5

• Standardised procedures

Answer 5

• all factors should remain constant aside from IV (standardisation)
  
  • lower variation in extraneous variables (e.g. time of day)
• lower/ no systematic bias for one of the conditions

Question 6

• Random assignment

Answer 6

• 2 main procedures
  - ppts assigned to experimental or control group using proper randomising procedure
  - only used when ppts take part in 1 condition
  - ppts randomly assigned to complete conditions in different orders
  - only used when ppts take part in more than 1 condition

Question 7

random

Answer 7

(to draw conclusions about causality) – each possible outcome has equal chance of being picked
- Possible procedures: toss a coin, throw a die, computer generation

Question 8

matching

Answer 8

ensuring ppts in experiment . Control groups are similar on variabes which might affect results (e.g. energy, IQ)

Question 9

Pre-test post-test sensitisation effects

Answer 9

• Checks if random assignment has equated groups on DV prior to experimental manipulation. So it is clear that different results due to manipulation of IV or pre-existing differences.
• Allows to test if there was a difference in performance between pre and post-test/

Question 10

Within subject design/ independent groups

Answer 10

• Some ppt different/ all conditions
  (-) fatigue/ boredom/ predict a practice
  -combat by counterbalancing

Question 11

Statistical significance

Answer 11

a determination that a relationship between two or more variables is caused by something other than chance. Statistical significance is used to provide evidence concerning the plausibility of the null hypothesis, which hypothesizes that there is nothing more than random chance at work in the data.