The diameters of circles (in mm) drawn in a design are given below:
Calculate the standard deviation and mean diameter of the circles.
[Hint: First make the data continuous by making the classes as 32.5-36.5, 36.5-40.5,
40.5-44.5, 44.5 - 48.5, 48.5 - 52.5 and then proceed.]
Let the assumed mean, A = 42.5 and h = 4
We obtain the following table from the given data:
We know that Mean,
∴
We know that Variance σ2 =
∴ σ2 =
We know that Standard Deviation = σ
∴ σ = √30.84 = 5.553
Ans. Mean = 43.5, Variance = 30.84 and Standard Deviation = 5.553