explain how results can be precise but not accurate?

Answer 1

Precision is the degree to which the results of multiple repeat experiments agree with one another. For instance if an experiment is repeated 3 times and the same result is obtained all three times, then the result is considered to be very precise. Accuracy is the degree to which the results of an experiment agree with the true or known value. An experiment or set of experiments may be very precise but not accurate. Less commonly, the results could be accurate but not precise. source
my physics book i just read it some where this week....Physics Demystified.

Answer 2

Nessa -
Results of an experiment are precise when the same result is obtained repeatedly. They are accurate only if they match up with the actual value of something. An instance when the results can be precise but not accurate is typically from an instrumental problem. For example, pretend your experiment is measuring something, but your ruler is faulty -- pretend some of the numbers are spaced incorrectly apart. You will keep getting the same answer every time to measure it and thus your answer will be PRECISE, but because your ruler is faulty, this value differs from the real answer, making your result NOT-ACCURATE.

Answer 3

One could say the odds of flipping a head with a fair coin is 1/3 , which is precise but not accurate, because it is actual 1/2 .

Answer 4

Lets say you have a piece of metal bar that you have to cut down to make a cube of exactly 1 cm cube. After you do it, you'll take the mesurements and find it to be accurate with your naked eyes. However, you need som high tech gadgets to actually measure the actual length and width of the cube that is made up of billions of atoms..there is nothing precise in this world..not even the atomic clock is not precise..just an example..

Answer 5

If you try to measure the circumference of the earth with a measuring-tape, you could be very precise and say what your result is to the nearest inch, but you would probably be wrong by several miles, so you would not be very accurate.

Answer 6

You can use a balance beam to weigh within milligrams, but, if you accidentally left a clump of dirt on the scale, you would be off by exactly the weight of the clump of dirt.

Your results would be precise to the milligram, but, inaccurate.

Large inaccuracy accompanied by precision is usually attributed to consistant additive error. Like, you where measuring from the wrong spot or someone cut off the last 3 millimeters of your measuring device.

Answer 7

Well precision and accuracy are two different things. Accuracy means a value from a standard object, while accuracy depends on someone using that instrument. Take for example a dart board, three darts landed on the bull's eye, so meaning to say that person has high accuracy as well as high precision.

Hoped that helped a bit!

Answer 8

Very cool question--thanks for asking. I see that there are some very nice answers posted already, and I won't try to repeat the excellent comments they have already provided.

When I performed experiments as an undergraduate physics student, I was required not only to provide an answer, but also to report on the error. Without getting all mathematical on you, I'll just say that it was kind of like significant digits on steroids.

Later in life, I encountered all sorts of people reporting survey results that said, for example, that 14.2% of respondents felt this way, etc. It was a blood sport to impute the number of actual responses based on the overzealous and overstated "accuracy" of the responses. (For example, perhaps 17 of 120 people said "yes" to a poorly-designed questionnaire, resulting in a 14.2% rate--essentially a fiction.)

Best luck in the future, Madame Curie.

Answer 9

Results are based on a first assumption and the logic follows precisely to a conclusion. And the conclusion may not neccessarily be the correct one if the first premise was not true.

Answer 10

Mr. Bush will argue he follow the prison manual exactly regarding torture in prisons. but in actuality there are 14000 prisoners in American custody in different places. He is precis by the argument that the law is regarding in America or American land. CIA is precise regarding the manual but totally in accurate.