Analysis and evaluation of experiments

What is the purpose of analysing experimental data?

To identify patterns, trends, and relationships in the results.

How can data be analysed?

• Plot graphs (line, bar, scatter).

• Calculate means, percentages, or rates.

• Compare results with predictions or control groups.

What is an anomaly?

A result that does not fit the pattern of the other data.

How should anomalies be treated?

Identify them, suggest possible causes, and decide whether to exclude them when calculating averages.

What is the purpose of evaluating an experiment?

To assess the quality, reliability, and validity of results, and suggest improvements.

What factors should be considered in evaluation?

• Accuracy of measurements.

• Reliability (consistency of results).

• Repeatability (same person repeating experiment).

• Reproducibility (different person repeating experiment).

• Control of variables.

• Sample size.

• Method limitations.

How can an experiment be improved?

• Use more precise equipment.

• Increase sample size.

• Control more variables.

• Repeat trials and calculate a mean.

• Use a control group for comparison.

• Reduce human error (automated measurements, blind testing).

What is the difference between reliability, repeatability, and reproducibility?

• Reliability: Consistency of results.

• Repeatability: Same person repeating experiment gets same results.

• Reproducibility: Different person or lab can get same results.

How should conclusions be drawn?

• Relate results to the hypothesis.

• Use evidence from data.

• Consider anomalies and explain them.

• State whether results support or refute predictions.

What is a limitation?

Something in the experiment that may have affected results (e.g., human error, environmental factors).

What type of graph should be used for continuous data?

Line graph.

What type of graph should be used for categorical data?

Bar chart.

How is a line of best fit used?

To show the overall trend, ignoring minor anomalies.

How can the rate of a process be calculated?

Rate = change in quantity ÷ time. Example: oxygen production by pondweed per minute.