IB Psychology 2015 - 2016 Year 2

The International School of Prague


Learning Objectives

Experimental design

  • Define the aim of a study.
  • State a research and null hypothesis of a study (HL only).
  • State the independent and dependent variable in an experiment.
  • State operational definitions of variables.
  • Describe potential confounding variables.
  • Explain the controls needed for an experiment (for example, maturation, contamination, placebo
  • Explain effects of participant and researcher expectations and bias (including demand characteristics, expectancy effect, observer bias).
  • Explain the use of single- and double‑blind techniques.
  • Discuss the strengths and limitations of experimental designs (for example, independent samples, repeated measures, matched pairs, single participant).

Sampling procedures

  • Discuss sampling techniques appropriate to quantitative research (for example, random, opportunity, systematic, stratified).
  • Discuss how participants are allocated to experimental and control groups (for example, matched pairs, random allocation).
  • Explain the concept of representative sampling.

Evaluation of research

  • Discuss the concepts of internal and external validity.
  • Discuss conditions that increase a study’s reliability.
  • Apply descriptive statistics to analyse data (for example, mean, median, mode, range, standard deviation).
  • Distinguish between levels of measurement (including nominal, ordinal, interval, ratio).
  • Apply appropriate graphing techniques to represent data (for example, bar chart, histogram, line graph).
  • Apply an appropriately chosen statistical test (for example, Wilcoxon matched‑pairs signed‑ranks test, Mann–Whitney U test, sign test, chi‑squared test) in order to determine the level of significance of data (HL only).

Supplementary Readings

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