Calculating Technical Error Measurement
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The difference between two measurements is called a variation in the measurements. Another word for this variation - or uncertainty in measurement - is "error." This calculating standard error of measurement "error" is not the same as a "mistake." It does not mean that
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you got the wrong answer. The error in measurement is a mathematical way to show the uncertainty in the measurement. calculating percentage error in measurement It is the difference between the result of the measurement and the true value of what you were measuring. The precision of a measuring instrument is determined by the smallest unit to which
Calculating Standard Error Of Estimate
it can measure. The precision is said to be the same as the smallest fractional or decimal division on the scale of the measuring instrument. Ways of Expressing Error in Measurement: 1. Greatest Possible Error: Because no measurement is exact, measurements are always made to the "nearest something", whether it is stated or not. The greatest possible error when measuring is considered to be one half calculating standard error of mean of that measuring unit. For example, you measure a length to be 3.4 cm. Since the measurement was made to the nearest tenth, the greatest possible error will be half of one tenth, or 0.05. 2. Tolerance intervals: Error in measurement may be represented by a tolerance interval (margin of error). Machines used in manufacturing often set tolerance intervals, or ranges in which product measurements will be tolerated or accepted before they are considered flawed. To determine the tolerance interval in a measurement, add and subtract one-half of the precision of the measuring instrument to the measurement. For example, if a measurement made with a metric ruler is 5.6 cm and the ruler has a precision of 0.1 cm, then the tolerance interval in this measurement is 5.6 0.05 cm, or from 5.55 cm to 5.65 cm. Any measurements within this range are "tolerated" or perceived as correct. Accuracy is a measure of how close the result of the measurement comes to the "true", "actual", or "accepted" value. (How close is your answer to the accepted value?) Tolerance is the greatest range of variation that can be allowed. (How much error in th
Download Full-text PDF Reliability, technical error of measurements and validity of instruments for nutritional status assessment of adults
Error Measurement Formula
in MalaysiaArticle (PDF Available) in Singapore medical journal 50(10):1013-8 · October 2009 with 881 ReadsSource: PubMed1st A
Standard Error Of Measurement Example
Geeta2nd H Jamaiyah+ 53rd M N SafizaLast Ahmad Faudzi Yusoff18.21 · Ministry of Health MalaysiaShow standard error of measurement definition more authorsAbstractThe Third National Health and Morbidity Survey Malaysia 2006 includes a nutritional status assessment of children. This study aimed to assess the inter- and intra-examiner http://www.regentsprep.org/regents/math/algebra/am3/LError.htm reliability, the technical error of measurement and the validity of instruments for measuring weight, height and waist circumference. A convenience sample of 130 adults working in a selected office setting was chosen to participate in the study, subject to the inclusion and exclusion study criteria. Two public health nurses, trained to follow a https://www.researchgate.net/publication/38084316_Reliability_technical_error_of_measurements_and_validity_of_instruments_for_nutritional_status_assessment_of_adults_in_Malaysia standard protocol, obtained the weight, height and waist circumference measurements. The weight was measured using the Tanita HD-318 digital weighing scale to the nearest 0.1 kg, and Seca Beam Scale to the nearest 0.01 kg. The height was measured using the Seca Bodymeter 206 and Stadiometer, both to the nearest 0.1 cm. The waist circumference was measured using the Seca circumference measuring tape S 201, to the nearest 0.1 cm. The intra-examiner reliability in descending order was weight and height followed by waist circumference. The height measurement, on average, using the test instrument, reported a recording of 0.4 cm higher than the reference instrument, with the upper and lower limits at 2.5 cm and 1.6 cm, respectively. The technical error of measurement and coefficient of variation of weight and height for both inter-examiner and intra-examiner measurements were all within acceptable limits (below five percent). The findings of this study suggest that weight, height and wais
of Accuracy Accuracy depends on the instrument you are measuring with. But as a general rule: The degree of accuracy is half a unit each side of the unit of measure Examples: When your instrument measures in http://www.mathsisfun.com/measure/error-measurement.html "1"s then any value between 6½ and 7½ is measured as "7" When your instrument measures in "2"s then any value between 7 and 9 is measured as "8" Plus or Minus We can show the error using the "Plus or Minus" sign: ± When the value could be between 6½ and 7½ 7 ±0.5 The error is ±0.5 When the value could be between 7 and 9 8 ±1 The error is standard error ±1 Example: a fence is measured as 12.5 meters long, accurate to 0.1 of a meter Accurate to 0.1 m means it could be up to 0.05 m either way: Length = 12.5 ±0.05 m So it could really be anywhere between 12.45 m and 12.55 m long. Absolute, Relative and Percentage Error The Absolute Error is the difference between the actual and measured value But ... when measuring we don't know standard error of the actual value! So we use the maximum possible error. In the example above the Absolute Error is 0.05 m What happened to the ± ... ? Well, we just want the size (the absolute value) of the difference. The Relative Error is the Absolute Error divided by the actual measurement. We don't know the actual measurement, so the best we can do is use the measured value: Relative Error = Absolute Error Measured Value The Percentage Error is the Relative Error shown as a percentage (see Percentage Error). Let us see them in an example: Example: fence (continued) Length = 12.5 ±0.05 m So: Absolute Error = 0.05 m And: Relative Error = 0.05 m = 0.004 12.5 m And: Percentage Error = 0.4% More examples: Example: The thermometer measures to the nearest 2 degrees. The temperature was measured as 38° C The temperature could be up to 1° either side of 38° (i.e. between 37° and 39°) Temperature = 38 ±1° So: Absolute Error = 1° And: Relative Error = 1° = 0.0263... 38° And: Percentage Error = 2.63...% Example: You measure the plant to be 80 cm high (to the nearest cm) This means you could be up to 0.5 cm wrong (the plant could be between 79.5 and 80
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