how to find that any number is both precise and accurate?
 

Asked by pannalal.malakar | 20th Jun, 2014, 09:25: AM

Expert Answer:

In the fields of math and science, the words accuracy and precision have more than a colloquial meaning. Accuracy and precision tend to be used synonymously, but they are separate ideas.

Precision refers to the closeness of various measurements for the same quantity. However, accuracy is the agreement of a particular value to the true value of the result.

In other words, Accuracy is a measure of the closeness to a true value. Precision is a measure of the variation of repeated results. High precision means high repeatability. High accuracy means high fidelity to an actual value. Precision can be a tricky number to calculate; the outcome is more of a best estimate.

For example, if the true value of the result is 2.00 g and a student 'A' takes two measurements and reports the results as 1.95 g and 1.93 g. These values are precise as they are close to each other but are not accurate.

Another student repeats the experiment and obtains 1.94 g and 2.05 g as the results for two measurements. These observations are neither precise nor accurate.

When a third student repeats these measurements and reports 2.01g and 1.99g as the result. These values are both precise and accurate.

Mesurements/g

1

2

Average (g)

Student A

1.95

1.93

1.940

Student B

1.94

2.05

1.995

Student C

2.01

1.99

2.00

Also, a system can be precise without being accurate and can be accurate without being precise, or it can be both.

Answered by Hanisha Vyas | 20th Jun, 2014, 11:51: AM