Accuracy and Precision

1. 1. Explain the difference between accuracy and precision.

You measure the mass of an object five times: [10.0 g, 10.1 g, 10.0 g, 10.2 g, 10.0 g]. The true mass is 10.0 g. Analyze the results.

• a) Accurate but not precise
  

• b) Precise but not accurate
  

• c) Both accurate and precise
  

• d) Neither accurate nor precise

2. Why is it important to report measurement uncertainty?

You measure a length as 25.4 cm with an uncertainty of ±0.3 cm. How does this affect the interpretation of your results?

• a) It doesn't affect the interpretation.

• b) It means the true length is likely between 25.1 cm and 25.7 cm.
  

• c) It indicates the measurement is unreliable.
  

• d) It shows that the measurement is precise.

3. How can systematic errors affect measurement accuracy?

A thermometer consistently reads 2°C higher than the actual temperature. How does this impact your results?

• a) It introduces a random error.

• b) It leads to results that are inconsistent.

• c) It introduces a systematic error, leading to inaccurate results.
  

• d) It has no impact on the results.

  
  

4. Identify sources of random errors.

You weigh an object multiple times and get [100.1 g, 100.3 g, 100.2 g, 100.4 g]. What could cause the variations?

• a) Systematic errors

• b) Calibration errors
  

• c) Random errors
  

• d) No errors

  
  

5. Describe how precision is measured.

You measure a liquid’s volume: [12.01 mL, 12.02 mL, 12.00 mL, 12.03 mL]. How precise are your measurements?

• a) Very precise

• b) Not precise
  

• c) Moderately precise
  

• d) No precision

  
  

6. Accurate and precise measurements.

You take three measurements: [25.0 g, 25.1 g, 24.9 g]. The true value is 25.0 g. Are these measurements accurate, precise, or both?

• a) Accurate but not precise
  

• b) Precise but not accurate
  

• d) Neither accurate nor precise

  
  

• c) Both accurate and precise
  

7. Improving precision in measurements.

You measure a quantity three times: [50.0 mL, 49.9 mL, 50.1 mL]. Suggest ways to improve precision.

• a) Use a different measurement tool.
  

• b) Ensure consistent techniques.
  

• c) Measure only once.
  

• d) Use a smaller sample size.

  
  

8. Systematic vs. random errors.

Your scale reads 0.5 g too high every time, and you also have fluctuating readings. Which are systematic and which are random errors?

• a) Systematic: fluctuating readings, Random: 0.5 g too high
  

• c) Both are random errors
  

• d) Both are systematic errors

  
  

• b) Systematic: 0.5 g too high, Random: fluctuating readings
  

9. Role of significant figures.

You have measurements: 123.45 mL, 123.5 mL, and 123 mL. How do significant figures affect the uncertainty?

• a) They do not affect uncertainty.

• b) They determine the precision of the measurement.
  

• c) They are irrelevant.
  

• d) They only apply to large measurements.

  
  

10. Calculate percent error.

You measured 98 g, but the true mass is 100 g. Calculate the percent error and discuss its significance.

• a) 2%, indicating a small deviation.
  

• b) 10%, indicating a significant deviation.
  

• c) 5%, indicating a moderate deviation.
  

• d) 1%, indicating an insignificant deviation.