A psychologist investigated the relationship between type of attachment in childhood and success in later adult relationships. He published a questionnaire in a local newspaper. The participants were people who read the newspaper, filled in the questionnaire and sent it to the psychologist. Participants’ answers to the questions were used to decide whether they had been securely or insecurely attached as children. The participants who were identified as securely attached children were more likely to have successful adult relationships than those identified as insecurely attached children.
(a) Identify the sampling technique used in this study. Outline one weakness of using this sampling method.
A teacher has worked in the same primary school for two years. While chatting to the children, she is concerned to find that the majority of them come to school without having eaten a healthy breakfast. In her opinion, children who eat ‘a decent breakfast’ learn to read more quickly and are better behaved than children who do not. She now wants to set up a pre-school breakfast club for the children so that they can all have this beneficial start to the day. The local authority is not willing to spend money on this project purely on the basis of the teacher’s opinion and insists on having scientific evidence for the claimed benefits of eating a healthy breakfast.
(a) Explain why the teacher’s personal opinion cannot be accepted as scientific evidence.
Refer to some of the major features of science in your answer.
A psychologist at the local university agrees to carry out a study to investigate the claim that eating a healthy breakfast improves reading skills. He has access to 400 five-year-old children from 10 local schools, and decides to use 100 children (50 in the experimental group and 50 in the control group). Since the children are so young, he needs to obtain parental consent for them to take part in his study.
study at the same time on the same group of children. The aim of this observational study is to test the idea that eating a healthy breakfast affects playground behaviour.
Design an observational study to investigate the effects of a healthy breakfast on playground behaviour. Include in your answer sufficient detail to allow for reasonable replication of the study. You should state the hypothesis you are setting out to test.
In your answer, refer to:
• an appropriate method of investigation
• materials/apparatus and procedure.
Justify your design decisions.
(Total 35 marks)
Psychologists often need to select participants to take part in research. The descriptions below are all types of sampling method.
A The psychologist puts an advert in a newspaper, asking for participants.
B The psychologist uses lists of students in a university and selects every tenth student to take part.
C The psychologist asks some of his psychology students to take part in the research.
In the table below, write which description, A, B, C, or D, matches each sampling method.
(Total 3 marks)
Psychological research suggests an association between birth order and certain abilities. For example, first-born children are often logical in their thinking whereas later-born children tend to be more creative. A psychologist wonders whether this might mean that birth order is associated with different career choices. She decides to investigate and asks 50 artists and 65 lawyers whether they were the first-born child in the family or not.
(a) Write a non-directional hypothesis for this study.
She analysed her data using a statistical test and calculated a value of = 2.27. She then looked at the relevant table to see whether this value was statistically significant. An extract from the table is provided below.
Table: Critical values of
Calculated value of must be equal to or exceed the table (critical) values for
significance at the level shown
(c) Imagine that you are writing the results section of the report on this investigation. Using information from the description of the study above and the relevant information from the statistical table, provide contents suitable for the results section.
You must provide all of the following:
• an appropriately labelled contingency table a sketch of an appropriately labelled bar chart
• identification of the appropriate statistical test with justification for its use
• identification of an appropriate significance level
• a statement of the results of the statistical test in relation to the hypothesis.