A researcher is looking to test the effects of caffeine on sleep, she invites 50 people to her laboratory: Research and methods Case Study, DMU, UK

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 8 pm every evening and the other half 2 decaffeinated drinks at 8 pm. The groups are not informed whether they consume caffeine or not. Afterward, she compares their sleep.

A. Identify the independent variable and dependent variable.

B. Write a non-directional hypothesis for the study.

C. Explain one strength and one limitation of laboratory experiments in relation to the case

D. Explain the steps, how the researcher could randomly allocate the participants randomly to the conditions of this experiment

2. 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.

A. Should the hypothesis be directional? Explain your answer

B. What percentage of the students reported that they would be able to concentrate better if they listened to music while they worked?

C. Identify the independent variable and dependent variable

D. Explain why using stratified sampling might improve this study.

E. The data collected in this study is primary data. Explain what is meant by ‘primary data’

F. The psychologist interviewed the students afterward to collect qualitative data, describe two differences between quantitative and qualitative data.