Plan an investigation to test the effect of an independent variable on a dependent variable. 12
Hypothesis linking IV and DV; IV range with intervals; DV with units and method of measurement; control variables and how controlled; clear step-by-step method; repeats for reliability; risk assessment; method of data analysis (graph/statistics).
Explain how you would ensure reliability in an investigation.
Repeat measurements; calculate mean; remove anomalies; use consistent method and equipment.
Explain how you would ensure validity in an investigation.
Control variables carefully; only change IV; ensure method measures intended outcome.
Evaluate an experimental method.
Identify a limitation; explain its effect on results; suggest a realistic improvement; explain how it improves accuracy or reliability.
Describe and explain a trend in data.
Describe overall pattern; support with data; explain using scientific reasoning.
Explain why anomalies may occur.
Random error; equipment limitations; human error; environmental changes.
Explain how you would improve accuracy.
Use more precise equipment; reduce human error; calibrate equipment; repeat measurements.
Explain how a risk assessment reduces risk.
Identify hazard; describe risk; explain control measure; link to reduced likelihood or severity.
Explain the importance of repeats.
Reduce random error; increase reliability; allow calculation of mean.
Explain how standard deviation helps interpret data.
Shows spread of data; smaller SD means more reliable results; allows comparison between data sets.
Explain how you would analyse data collected.
Calculate mean; plot graph; identify trend; identify anomalies; apply statistics if appropriate.
Explain limitations of experimental data.
Small sample size; uncontrolled variables; measurement uncertainty; equipment limits.
Explain how to improve reliability and validity.
Repeats; control variables; better equipment; automated measurements.
Explain the difference between accuracy and precision.
Accuracy is closeness to true value; precision is consistency of measurements.
Explain how a conclusion should be written.
Refer to results; link to hypothesis; avoid opinion; use data as evidence.
Describe how you would carry out an investigation to test the effect of X on Y 8 marker
- Name the independent variable; - Name the dependent variable; - Describe how the dependent variable is measured (equipment + units); - Outline basic method steps; - Mention repeats for reliability; - State how results are recorded
Describe the risks and safety precautions for the investigation
- Identify hazard; - State the risk; - Give a control measure; - Explain how it reduces risk
Describe a method to investigate the effect of X on Y
- Set independent variable (state range + how); - Keep control variables constant (state how); - Measure dependent variable (equipment + units); - Repeat measurements (≥3); - Change IV and repeat; - Record results in table with headings and units
