NPTEL IIT Guwahati

i) Instrumental errors :

Zero offset (instrument does not read zero when input is zero) or incorrect calibration of the instrument or changes of calibration conditions (due change in temperature, pressure or any other environmental changes) are the example of instrumental errors. Zero error can be detected before hand and all the observations are corrected accordingly. For the purpose of this course it can be assumed that the given instrument is calibrated correctly.

(ii)Experimenter's Bias :

This is a common source of error arising from some bias of the experimenter and is difficult to eradicate. For example parallax error in reading an analog meter is often encountered if care is not taken to view the indicator needle perpendicular to the meter face.

Systematic errors are hard to handle. They are best identified and eliminated.

Fluctuations in the instrumental measuring processes results in random errors. The effect of random errors can be minimized by appropriate data processing techniques.
2. Probable error : It is known from experience that any long sequence of independent observations of a variable x shows up fluctuating deviation from average. The probability of occurrence of these deviations is expressed by the normal distribution


Error Analysis and Data Analysis by Least Square Fitting	Print this page
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i) Instrumental errors : Zero offset (instrument does not read zero when input is zero) or incorrect calibration of the instrument or changes of calibration conditions (due change in temperature, pressure or any other environmental changes) are the example of instrumental errors. Zero error can be detected before hand and all the observations are corrected accordingly. For the purpose of this course it can be assumed that the given instrument is calibrated correctly. (ii)Experimenter's Bias : This is a common source of error arising from some bias of the experimenter and is difficult to eradicate. For example parallax error in reading an analog meter is often encountered if care is not taken to view the indicator needle perpendicular to the meter face. Systematic errors are hard to handle. They are best identified and eliminated. (b) Random Error : Fluctuations in the instrumental measuring processes results in random errors. The effect of random errors can be minimized by appropriate data processing techniques. 2. Probable error : It is known from experience that any long sequence of independent observations of a variable x shows up fluctuating deviation from average. The probability of occurrence of these deviations is expressed by the normal distribution
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