{"id":6119,"date":"2022-07-07T19:29:38","date_gmt":"2022-07-07T19:29:38","guid":{"rendered":"https:\/\/physics.educour.in\/isc-physics\/?p=6119"},"modified":"2022-07-07T20:06:40","modified_gmt":"2022-07-07T20:06:40","slug":"accuracy-and-precision","status":"publish","type":"post","link":"https:\/\/physics.educour.in\/isc-physics\/accuracy-and-precision\/","title":{"rendered":"Accuracy and Precision"},"content":{"rendered":"\t\t
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ACCURACY and PRECISION<\/strong><\/span><\/h1>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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ACCURACY:<\/u><\/strong>\u00a0<\/span><\/h2>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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\u201cThe extent upto which an observed value agrees with the true value of a quantity is known as <\/strong>accuracy<\/strong>\u201d. <\/strong><\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Lesser the difference between the true value and the measured value (i.e. lesser the error), more is the accuracy in the measurement. So, accuracy is inversely related to the error involved in the measurement.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Example:<\/em><\/strong><\/span> Suppose the true value of a quantity is 2.35m. One of the measurements reads the value as 2.32m and another gets the value as 2.34m. The first measurement involves 0.03m of error, whereas the error involved in the second measurement is 0.01m.\u00a0 Obviously, the second measurement is more accurate. This is because in the second measurement the closer to the true value and involves lesser error. <\/em><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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The instrument which gives repeated readings close to the true value of the physical quantity being measured is an accurate instrument.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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PRECISION<\/u><\/strong><\/span><\/h2>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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“The precision of an observed value tells to what resolution (least count) the quantity is measured”. <\/strong><\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Thus if all the observed values are very close to one another (even if they are not close to the true value), are considered precise.<\/span><\/p>

An instrument which gives a tight cluster of repeated results is a precise instrument. It is directly related to the least count of the instrument. Lesser the least count of the instrument, the more is the precision. <\/strong><\/span><\/span><\/p>

Since precision depends on the resolution (least count) of the instrument, it is also related to the significant figures. More the number of significant figures in the measured value of the quantity, the more is the precision in measurement<\/span><\/strong>.<\/span><\/span><\/p>

To understand the difference between Accuracy and Precision more clearly, let us consider an example.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Example:<\/em><\/strong><\/span> Suppose the true value of a certain length is near 3.678 cm. In one experiment, using a measuring instrument of resolution 0.1 cm, the measured value is found to be 3.5 cm, while in another experiment using a measuring device of greater resolution (lesser least count), say 0.01 cm, and the length is determined to be 3.38 cm. The first measurement has more accuracy (because it is closer to the true value) but less precision (its resolution is only 0.1 cm), while the second measurement is less accurate but more precise (its resolution is only 0.01 cm). Thus every measurement is approximate due to errors in measurement.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

ACCURACY and PRECISION ACCURACY:\u00a0 \u201cThe extent upto which an observed value agrees with the true value of a quantity is known as accuracy\u201d. Lesser the difference between the true value and the measured value (i.e. lesser the error), more is the accuracy in the measurement. So, accuracy is inversely related to the error involved in … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"post_folder":[43],"class_list":["post-6119","post","type-post","status-publish","format-standard","hentry","category-11-lecture-notes"],"_links":{"self":[{"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/posts\/6119","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/comments?post=6119"}],"version-history":[{"count":43,"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/posts\/6119\/revisions"}],"predecessor-version":[{"id":6166,"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/posts\/6119\/revisions\/6166"}],"wp:attachment":[{"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/media?parent=6119"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/categories?post=6119"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/tags?post=6119"},{"taxonomy":"post_folder","embeddable":true,"href":"https:\/\/physics.educour.in\/isc-physics\/wp-json\/wp\/v2\/post_folder?post=6119"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}