Precision, Accuracy, and Percent Error:
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Suppose a student measures the volume of an aluminum block three times and records the following data: 8.42 cm^3, 8.41 cm^3, and 8.40 cm^3. The accepted volume of the aluminum block is 11.5 cm^3. Comment on the accuracy and precision of the data. Provide an explanation for your answer.
Answer: This data is not accurate because the 3 measurements are close together but less than the accepted volume of the aluminum block of 11.5 cm^3 but at least 3 centimeters.
Am I right? I tend to confuse accuracy and precision. They are almost the same but at the same its confusing to deciper each.
The close together means high precision.
BUT
The wrong answer means poor accuracy.
You are correct in noting that accuracy and precision are related but distinct concepts in measurement. Let's clarify them:
Precision refers to the reproducibility and consistency of measurements. In this case, the three measurements of the volume of the aluminum block (8.42 cm^3, 8.41 cm^3, and 8.40 cm^3) are very close to one another. Therefore, they exhibit high precision because they are consistent and "precise" in terms of their closeness to each other.
Accuracy, on the other hand, refers to how close a measurement is to the true or accepted value. In this case, the accepted volume of the aluminum block is 11.5 cm^3. The measured values of 8.42 cm^3, 8.41 cm^3, and 8.40 cm^3 are all significantly lower than the accepted value. Therefore, the measurements are not accurate because they deviate from the true value.
To summarize, the data in this case exhibit high precision because the measurements are close to each other, but they lack accuracy because the measured values are significantly lower than the accepted value.