MediumChemistryHigh School (11–12)Atoms and Molecules › Measurement, Units and Significant FiguresNumericalpython
A standard weight of exactly 4.000 g is weighed three times by three analysts.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A standard weight of exactly is weighed three times by three analysts. Arun gets , and . Bela gets , and . Chitra gets , and . For each, find the mean and the spread (largest minus smallest), and say whether the readings are precise, accurate, both or neither.
Need a reminder? The key ideaShow
Precision is how close repeated readings are to each other. Accuracy is how close they are to the true value. The spread of the readings shows the precision, and the distance of their mean from the true value shows the accuracy.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Arun. Mean , spread . Precise, but too low: not accurate.
Step 2. Bela. Mean , spread . Accurate on average, but not precise.
Step 3. Chitra. Mean , spread . Both precise and accurate.
Answer: Arun is precise only; Bela is accurate only; Chitra is both.
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