Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83 based; site hou2b.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!lll-crg!dual!qantel!ihnp4!houxm!hou2b!halle From: halle@hou2b.UUCP (J.HALLE) Newsgroups: net.med Subject: Re: The Perils of Nutrasweet: digits of precision Message-ID: <592@hou2b.UUCP> Date: Tue, 13-Aug-85 14:42:03 EDT Article-I.D.: hou2b.592 Posted: Tue Aug 13 14:42:03 1985 Date-Received: Sat, 17-Aug-85 06:45:42 EDT References: <587@rtech.UUCP> Organization: AT&T Bell Labs, Holmdel NJ Lines: 14 Before this debate gets too out of hand, it might be prudent to remind people what the terms mean. Accuracy and precision are NOT synonymous. Precision refers to the number of significant figures, but is not necessarily a good indicator of accuracy. Accuracy refers to the reliability of the stated value. E.g., you could measure something to be 13.246792 inches long, but if your ruler was only so-so and/or your measurements had a lot of scatter, you could be accurate only to perhaps two decimal places. (13.246792 +/- 0.05, e.g.) It is not necessarily incorrect to state it this way (although it is bad form). 0.007% has three decimal points worth of precision, but that merely tells you the size of the scale. Its accuracy is unknown, though implied. Depending on the measurement method, three decimal places of precision could be "significant," or it could be a crude estimate. More information is required.