This lesson completes the Science inquiry strand: collecting and analysing data, drawing conclusions, evaluating research, and communicating findings.
1. Data collection
Qualitative data (interviews — focus group/individual, structured/semi-structured; open-ended surveys) and quantitative data (objective physiological measures — heart rate, breathing rate, galvanic skin response; subjective measures — rating scales such as Likert scales). Mixed methods combine both. Distinguish subjective from objective data.
2. Processing and analysing data
- Data displays: graphs (scatterplot, column, line, histogram) and tables (summary, frequency).
- Central tendency: calculate and interpret the mean and median.
- Correlation: interpret Pearson's correlation coefficient as a measure of the strength and direction of a linear relationship (closer to +1 or −1 = stronger; the sign gives direction).
3. Drawing conclusions
Conclusions must be evidence-based, consistent with the psychological evidence, and relevant to the hypothesis or inquiry question.
4. Evaluating research
- Validity — the extent to which a study measures what it intends to measure (internal and external validity).
- Reliability — how consistent/stable the results are; the extent to which a method produces similar results under similar conditions (test-retest and inter-rater reliability).
- Generalisability — applying findings from a sample to a population.
- Suggest improvements, consider ethical implications, and critically evaluate scientific sources.
5. Communicating
Use appropriate psychological terminology and acknowledge sources of information using appropriate referencing (researcher name and date).
Work through these together.
Calculating central tendency
For the dataset 6, 5, 7, 7, 8, 9, 5, 6, 7, 4, calculate together (to two decimal places):
Mean:
Median:
Interpreting correlation coefficients
For each coefficient, state the strength and direction:
0.91:
0.24:
−0.86:
Answer independently, using examination-style directive verbs.
Q1. For the dataset 6, 5, 7, 7, 8, 9, 5, 6, 7, 4, calculate the mean and median to two decimal places. (2 marks)
Q2. Explain what 'reliability' means in the context of psychological research, and outline one way it can be improved. (4 marks)
Q3. Define the concept of 'validity'. (1 mark)
Q4. A study reports a correlation coefficient of −0.86 between a factor and sleep deprivation. Interpret this coefficient. (4 marks)
Q5. Justify why using an interview to assess motivation may be a better choice than using a checklist or rating scale. (4 marks)