Question

The diameter of a wire as measured by screw gauge was found to be 2.620, 2.625, 2/628 and 2.626 cm. Calculate mean value of diameter.
(A) 2.625 cm
(B) 2.62 cm
(C) 2.63 cm
(D) None of the above

Answer 1

Hint To find the mean value of the diameter we need to first find the sum of all the values that are mentioned in the question. Then we have to divide the sum by the number of values that are present in the question. This question should be solved in the similar way as we solve questions of arithmetic mean.

Complete step by step answer
We know that the formula to find the mean value of diameter is given as:
${a_m} = \dfrac{{2.620 + 2.625 + 2.630 + 2.628 + 2.626}}{5}$
$\Rightarrow 2.6258cm$
$= 2.626cm$
In the above expression, what we did is, we just put the values in the numerator and then divided the sum by mentioning the total number of quantities that is mentioned in the question in the denominator.
Hence the mean value of the diameter is 2.626 cm or 2.63 cm.

So, the correct answer is option B.

NoteIt should be known to us that a screw gauge is defined as the device that is used for the measurement of the small objects, which in other ways would not be possible to measure using any other ordinary scale. The scale can measure things as small as 1 mm, which is referred to as the least count. But in case of screw gauge we can measure things as small as I micrometre or we can say 0.001 mm.
The screw gauge consists of a U-shaped frame fitted with a screwed spindle which is in connection to a thimble. It should also be known to us that the thickness of a metal sheet is expressed in the form of a gauge number.