The result I got about the errors of measured values in the operation of measurement was as follows.
When I divided the measured values I got by measuring length by micrometer into a true value, a working value and a perceived value, and examined the relations among these values, it was found that the working value is near to the true one, while the perceived one is far from the true one.
This is caused by incorrect reading of scale marks. And personal differences are comparatively little in the working values, but they are very remarkable in the perceived values.
This comes from the fact that the working value is measured by mechanical operation, while the perceived value depends upon perceptive recognition through vision.
I give the ways of incorrect reading: (1) counting the number of 1mm scale marks of sleeve, (2) not reading 0.5mm scale marks of sleeve at all, (3) unnecessary reading of 0.5mm scale marks of sleeve, (4) incorrect reading of thimble.
Among these (3) cases appear most remarkly. It is clear that these errors had relations with the thickness of 1 ines of scale marks.
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