Controller

The output Controller of the company, in the control of 50 randomly selected products, found that 37 of them had no defects, eight had only one flaw, three had two defects, and two products had three defects. Determine the standard deviation and coefficient of variation.

Correct answer:

s =  0.7746
c =  1.9365

Step-by-step explanation:

$$\begin{gathered} m=(37\cdot 0+8\cdot 1+3\cdot 2+2\cdot 3)/50=\frac{2}{5}=0.4 \\ r=(37\cdot (0-m{)}^2+8\cdot (1-m{)}^2+3\cdot (2-m{)}^2+2\cdot (3-m{)}^2)/50=(37\cdot (0-0.4{)}^2+8\cdot (1-0.4{)}^2+3\cdot (2-0.4{)}^2+2\cdot (3-0.4{)}^2)/50=\frac{3}{5}=0.6 \\ s=\sqrt{r}=\sqrt{0.6}=0.7746 \end{gathered}$$

$c=s/|m|=0.7746/|0.4|=1.9365$

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