experimental design

Question 1

study

Answer 1

Does drinking SpeedUpp energy drink cause people to be more talkative than water?

• Participants get either SpeedUpp or water to drink.
• Researchers measure the words spoken per minute in the 5 mins after drinking either / both drinks.

Question 2

intro

Answer 2

Experimental Design refers to the way in which participant are arranged within different experimental conditions.

• Independent Groups
• Repeated Measures
• Matched Pairs

Question 3

independent groups

Answer 3

• Participants are split into 2 groups and each only experience one level of IV. The mean score of words spoken would then be compared.
• SpeedUpp experiment.

• Group 1 experiences condition A.
• Drinking the energy drink.

• Group 2 experiences condition B.
• Drinking water.

Question 4

repeated measures

Answer 4

• All participants experience all levels of IV and then the 2 mean scores from both conditions would be compared.
• SpeedUpp experiment.
• Participants experience condition A.
• Drinking the energy drink.

• Participants experience condition B.
• Drinking water.

Question 5

matched pairs

Answer 5

• Participants would be paired up based on a trait relevant to the study and then split into different conditions.
• Eg. IQ in a memory study.
• SpeedUpp experiment.
• Participants are paired based on chattiness / outgoing
• The 1st and 2nd most talkative participants are paired etc.
• Each partner then experiences 1 condition (like independent groups)
• Their results are compared.

Question 6

eval-repeated measures

Answer 6

1. Order effects can impact the results - task completed in one condition, could have an impact on the task completed in another.
   • Boredom / fatigue.
   • SpeedUpp could continue to affect people.
   • Counterbalancing is used to counteract this.

100 Participants
Split into 2
groups of 50-group 1 experience condition A and group 2 experience condition B, then swap

In each condition half the participants are doing it first-counterbalancing is the ABBA principle

2.demand characteristics can be an issue because people could work out the aim of the study

pros/

1. Participant variables are being controlled because the same participants are in both conditions.
2. More economical than independent groups or matched pairs as half the amount of participants are needed.

Question 7

eval-independent groups

Answer 7

cons/

• Participant variables can confound the results.
• Random allocation is used in an attempt to deal with this.
• Less economical - 2x times as many participants are needed to achieve the same as in a repeated measures design.

pros/
• No order effects - Participants are less likely to guess the aim as they have only experienced
1 condition.-less demand characteristics aswell

Question 8

eval-matched pairs

Answer 8

cons/
• Less economical than other designs, especially if a pre-test is required.

pros/

• Order effects and demand characteristics are less of a problem.
• Order effects and demand characteristics are less of an issue because participants only take part in one condition.
-Impact of participant variables are reduced but can never be eliminated completely