Channelling Nero Wolfe?

[bcholmes]

"Contact is not a verb."
"Yes sir, it is. Last time you corrected me I went home and looked it up. Transitive and intransitive."
"Not in this house, it isn't!"

A coupl'a times I've watched people quibble about the difference between the words "precision" and "accuracy". I've never really felt that their definitions were different.

I popped over to dictionary.com today and found that the second definition of accuracy is "Precision; exactness". Hurm.

Comments

Re: Precision and accuracy.

[purplesofa.livejournal.com]

I concur with baratron's explanation.

To the layperson, "precise" and "accurate" are prety much interchangeable. But scientists and statisticians have applied more (ahem) precise meanings to the terms.

In statistics, we would say that precision refers to the size of the "confidence interval". E.g. if you do some sampling to estimate that the average Toronto subway car contains 150 people, you might be off by plus or minus 20 people. That's the level of precision, and it can be computed by statistical methods.

In statistics, the opposite of accuracy is bias. If you had sampled the subway car populations only at rush-hour, you would get an upward bias, and thus an inaccurate estimate. Bias can't usually be computed - or else it would have been prevented in the first place, by more accurate measurement methods.