Data recording, analysis and presentation — OCR A-Level Psychology Revision
This topic covers the procedures and processes for collecting, analysing, and presenting psychological data, including the use of descriptive and inferenti
Topic Synopsis
This topic covers the procedures and processes for collecting, analysing, and presenting psychological data, including the use of descriptive and inferential statistics, data levels, and graphical representation.
Key Concepts & Core Principles
- Quantitative vs. Qualitative Data: Understanding the nature, strengths, and weaknesses of numerical (e.g., scores) and non-numerical (e.g., interview transcripts) data.
- Levels of Measurement: Differentiating between nominal, ordinal, interval, and ratio data, as this dictates which statistical tests can be used.
- Descriptive Statistics: Calculating and interpreting measures of central tendency (mean, median, mode) and dispersion (range, standard deviation) to summarise data sets.
- Inferential Statistics: Knowing the purpose of inferential tests (e.g., Mann-Whitney U, Wilcoxon, Chi-Squared, Spearman's Rho) to determine statistical significance and when to apply each based on design, data type, and hypothesis.
- Data Visualisation: Selecting and constructing appropriate graphs (bar charts, histograms, scattergrams) to effectively present different types of data.
Exam Tips & Revision Strategies
- Practice selecting the correct statistical test using a decision tree or flow chart
- Ensure you can convert between standard form and decimal form accurately
- Always label axes and provide titles for any graphs or charts constructed
- Be prepared to justify why a specific measure of central tendency or dispersion is most appropriate for a given data set
- Memorize the symbols for significance and inequality (e.g., <, >, ∝) as they are required for reporting results
Common Misconceptions & Mistakes to Avoid
- Confusing measures of central tendency with measures of dispersion
- Selecting an inappropriate statistical test for the data level or experimental design
- Misinterpreting significance levels (e.g., confusing p < 0.05 with a 5% chance of being wrong)
- Incorrectly identifying the level of measurement (nominal vs ordinal vs interval)
- Failing to use the correct number of significant figures in calculations
Examiner Marking Points
- Design and use of raw data recording tables
- Application of significant figures and decimal/standard form
- Identification of data levels (nominal, ordinal, interval)
- Distinction between quantitative/qualitative and primary/secondary data
- Calculation and application of measures of central tendency (mean, median, mode)
- Calculation and application of measures of dispersion (variance, range, standard deviation)
- Selection and construction of appropriate graphical displays (line graphs, pie charts, bar charts, histograms, scatter diagrams)
- Understanding of normal and skewed distribution curves