DE MONTFORT UNIVERSITY INTERNATIONAL COLLEGE (DMUIC)
Programme: IYZ Psychology
ASSIGNMENT 2: Case Study Report
Credit Value: 12
Owning Board: Joint Academic Board (DMU/OIEG)
Faculty: University Wide Learning (DMU)
Module Tutor: Sarah Gannon.
Assessment Weighting: 50% with 40% threshold
Word Count: 1,200 (Guidance – not including references, tables/fig’s)
(only up to 10% plus or minus this guidance is allowed)
You must demonstrate learning outcomes:
2. Identify weaknesses in specific methodologies and understand the relative merits of quantitative and qualitative approaches
3. Apply the techniques relevant to conducting descriptive and inferential statistics
Assessment Brief given on: Week 7
Draft Submission: week 9
Assessment due date: Friday 11th March 2022 (week 9) 09:00 via Turnitin Blackboard
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Questions should be answered in order, in a narrative format, and with additional discussion as required. Please note the word count above.
Read the items below and answer the questions that follow.
1. A researcher is looking to test the effects of caffeine on sleep, she invites 50 people to her laboratory to sleep for 7 days. She gives half the group 2 caffeinated drinks at 8pm every evening and the other half 2 decaffeinated drinks at 8pm. The groups are not informed whether they consume caffeine or not. Afterwards, she compares their sleep.
A. Identify the independent variable and dependent variable (2 marks)
B. Write a non-directional hypothesis for the study (2 marks)
C. Explain one strength and one limitation of laboratory experiments in relation to the case (4 marks)
D. Explain the steps, how the researcher could randomly allocate the participants randomly to the conditions of this experiment (4 marks)
Students often claim that listening to music helps them to concentrate. A psychologist was not aware of any previous research in this area. She decided to investigate this claim.
Fifty students from a local college volunteered to take part in her study. They each answered the following question:
‘Do you think that you concentrate on your work ‘better’, ‘worse’ or ‘the same’ if you listen to music while working?’
She obtained the results in Table 1.
Table 1: Responses to question – ‘Do you think that you concentrate on your work ‘better’, ‘worse’ or ‘the same’ if you listen to music while working?’
Better Worse The same
27 8 15
A. Should the hypothesis be directional? Explain your answer (2 marks)
B. What percentage of the students reported that they would be able to concentrate
better’ if they listened to music while they worked? (2 marks)
C. Identify the independent variable and dependent variable (2 marks)
D. Explain why using stratified sampling might improve this study. (2 marks)
E. The data collected in this study is primary data. Explain what is meant by ‘primary data’ (2 marks)
F. The psychologist interviewed the students afterwards to collect qualitative data, describe two differences between quantitative and qualitative data. (4 marks)
A psychologist obtained a volunteer sample of 10 students aged 16 years old from a college. Using a repeated measures design, participants were asked to complete two puzzle tasks as quickly as possible.
Task A was to find 10 differences in a ‘spot the difference’ puzzle while working in silence.
Task B was to find 10 differences in another ‘spot the difference’ puzzle while listening to music through headphones.
The tasks were counterbalanced and the time taken to complete each task was recorded for each student.
Table 2: Times taken (in seconds) to complete Task A (silence) and Task B
Participant Task A (silence) Task B (music)
1 67 82
2 45 70
3 58 60
4 43 59
5 72 77
6 90 105
7 101 90
8 37 59
9 54 83
10 63 89
A. Explain one reason why the mean would be the most appropriate measure of central tendency to summarise the data in Table 2. (2 marks)
B. Calculate the mean values for both Task A and Task B. Show your workings. Give your answers in 3 significant figures (2 marks)
C. The psychologist used counterbalancing in the study, discuss the purpose of counterbalancing. (3 marks)
D. Identify two possible extraneous variables that the psychologist could have controlled in this study. Explain how this extraneous variable could affect the study if it was not controlled.
E. Evaluate repeated measures design with reference to the above case (4 marks)
A researcher is looking to study the effect of sleep deprivation on memory. He intends to divide participants into two groups and ask them to learn a list of 15 words. The first group will then be deprived of sleep for 24 hours, whilst the second group will maintain a normal level of rest.
Both groups will then be asked to recall the list of words.
Table 3. Number of words recalled.
No sleep for 24 hours Normal sleep
A. Identify and explain two possible extraneous variables that could potentially be confounding in this study. (4 marks)
B. Discuss whether a repeated measure design would be more suitable (4 marks)
C. Outline and explain at least two ethical principles that will need to be considered for this psychological research, as developed by the British Psychological Society. (6 marks)
D. Calculate the mean values for both groups. Give answers in 2 significant figures (2 marks)
E. What kind of conclusion could the researcher draw about the effect of sleep deprivation on memory? (4 marks)
A slimming club wanted to find out whether their programme was effective. They recorded the weights of ten members of the club when they first joined, and their weight after four months.
Table 4. Weight of Slimming Club Members
Slimming Club Member Starting Weight in kg Weight after Four months in kg Difference Sign
Lin 80 74
Alexandra 75 70
Jakub 125 126
Gurban 108 97
Paulina 96 82
Oliwia 70 70
Wiktoria 102 94
Veronika 128 129
Natalia 97 75
Marius 122 94
Table 5. Critical Values of S for the sign test
Level of significance for two-tailed test
Level of significance for one-tailed test
7 0 0
8 1 0
9 1 1
10 1 1
11 2 1
12 2 2
A. Write a suitable directional hypothesis for this study. (2 marks)
B. Use the sign test to work out whether the programme was effective for these members. Show your workings in the table. State the calculated value of S, the Critical value of S and whether your hypothesis is significant. (8 marks)
C. Calculate the mean weight loss for the study. (3 marks)
D. What might you now conclude about the effectiveness of the slimming programme, taking into consideration of the sign test outcome? How would you explain this? (4 marks)
6. The cognitive interview is a technique that has been adopted by some police forces in the UK. Many other police forces continue to use the standard interview technique which is the traditional method used when questioning suspects and eyewitnesses.
A researcher is employed to compare the effectiveness of both of these techniques. The researcher shows a set of films to 10 eye witnesses and then these 10 eyewitnesses are interviewed by both a police force that uses the cognitive technique and one police force that uses the standard interview technique. The information is gathered and scored on accuracy.
Table 6. Results from the eyewitnesses.
Mean accuracy score out of a maximum score of 100
Police Force A – uses cognitive interview 78
Police Force B – uses standard interview 65
A. Explain why this study is a natural experiment. (3 marks)
B. What do the results show in table 6? What conclusions could you draw from this? (4 marks)
C. The researcher further compared the accuracy scores for male and female police officers. This part of the study is a quasi-experiment. Explain why this is the case (3 marks)
D. Discuss the use of natural experiments in reference to this study and give further evidence to support. (10 marks)
You should upload your assignment; including references list which follows the Harvard referencing system, onto Turnitin by 9.00a.m Friday 11th March 2022