OCR A-Level Psychology H567
Research Methods and Techniques
Planning and Conducting Research
Data Recording, Analysis and Presentation
Report Writing and Scientific Communication
Practical Activities and the Nature of Science
Mathematical Requirements for Research Methods
Studying and Evaluating the Core Studies: The Common Framework
Core Studies: Social Area
Core Studies: Cognitive Area
Core Studies: Developmental Area
Core Studies: Biological Area
Core Studies: Individual Differences Area
Areas and Perspectives in Psychology
Debates in Psychology
Practical Applications of Psychology
Issues in Mental Health
Child PsychologyApplied option
Criminal PsychologyApplied option
Environmental PsychologyApplied option
Sport and Exercise PsychologyApplied option
Methodological Issues and Debates Running Through Applied Psychology
Mathematical Requirements for Research Methods
Calculating chi-square, sign test, Wilcoxon and Mann-Whitney values and reporting results
- 2 things to know
- Component 01
Overview
Recall questions on ranking tied scores, calculating expected frequencies and cell contributions to chi-square, finding N and S for the binomial sign test, and how to report and qualify a significant result.
What you need to know
Answer each one before you reveal it.
How is the expected frequency for a cell in a chi-square calculation worked out?
Questions from this subtopic
Each one with the model answer underneath.
- 1
How are tied scores dealt with when ranking data for a non-parametric test?
Model answer
They share the mean of the ranks they would have occupied, so two scores tied for third and fourth place are each given the rank 3.5.
- 2
How is the expected frequency for a cell in a chi-square calculation worked out?
Model answer
Multiply the row total by the column total and divide by the overall total, so a row total of 40 and a column total of 30 in a study of 100 gives an expected frequency of 12.
- 3
One cell has an observed frequency of 18 against an expected frequency of 12. What does this cell contribute to chi-square?
Model answer
The difference of 6 is squared to give 36 and divided by 12, so the cell contributes 3.
- 4
What does the value of chi-square get larger with?
Model answer
The size of the differences between the observed and expected frequencies.
- 5
What is the value of S in a binomial sign test?
Model answer
The number of participants showing the less frequent direction of change.
- 6
Fourteen participants take part; 11 improve and 3 get worse. State N and S for a binomial sign test.
Model answer
N is 14 and S is 3, because 3 is the smaller number of signs.
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