Question

Question 5. [11 marks] IChapter 2] Consider the following studies: Study 1: A study was conducted to see if music can influence people's ability to remember. Memory was tested by giving people a series of pictures to look at for 10 minutes and then asking them to answer a series of questions about the pictures. A memory score was computed based on their answers. 120 people were recruited and randomly allocated to one of 4 groups: the first group did the memory test while listening to classical music; the second group listened to country and western music; the third group listened to heavy metal music while the fourth group did the test in silence Study 2: The organiser of a major sporting event was interested in how many New Zealanders were willing to pay various prices for tickets to the final of the tournament Lists of registered supporters of local clubs were gathered and then a sample of 1000 people were randomly selected from the list. Everyone in the sample was sent a letter stating the proposed price of tickets and asking them if they would be willing to purchase tickets at that price. The sample had been randomly split into two groups, with half getting a letter saying that the tickets cost $40 while the rest got a letter saying that the ticket price was $50. The proportion of people saying they would buy tickets was recorded for each group. (a) Answer the following questions FOR EACH study: (i) Identify the groups that are being compared. (L.e., what treatments or factors of interest are being compared?) DO NOT also say what is being measured to make the comparison-you do this in (ii) What is being measured to compare these groups? ONLY describe the variable being measured. DO NOT also mention the groups being compared -you do this in (i) (ii) (ii) Would you describe the study as an experiment or an observational study? If it was an experiment, what part of the study design led you to this conclusion? - If it was an observational study, could an experiment have been easily carried out instead? If so, briefly explain how. If not, briefly explain why not [6 Marks total: 3 marks for each study]

Answer 1

Solution

Study 1

Part (1)

Factors: Type of music – 3 types + 1 control Answer 1

Part (2)

Variable: Memory Test Score Answer 2

Part (3)

This is an experiment. Respondents are grouped randomly and responses recorded for each group. A case of a Completely Randomised Design with 4 treatments. Answer 3

Study 2

Part (1)

Factors: Price Level – 2 levels Answer 4

Part (2)

Variable: Proportion of positive response, i.e., readiness to buy ticket Answer 5

Part (3)

This is an observational study. No experiment is possible in this case. Answer 6

DONE