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Fifty boxes each of 50 bolts were inspected for the number which were defective. The ...

Fifty boxes each of 50 bolts were inspected for the number which were defective. The following was the result
\(\begin{array}{c|c} \text{No. defective per box} & 4 & 5 & 6 & 7 & 8 & 9 \\ \hline \text{No. of boxes} & 2 & 7 & 17 & 10 & 8 & 6\end{array}\)
The mean and the median of the distribution are respectively
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  • A 6.7, 6
  • B 7.6, 5
  • C 5.7, 87
  • D 34, 6
Correct Answer: Option A
Explanation:
No of defective(x) No of boxes (f) \(fx\)
4 2 8
5 7 35
6 17 102
7 10 70
8 8 64
9 6 54
\(\sum\) 50 333



\(Mean = \frac{\sum fx}{\sum f}\)
= \(\frac{333}{50} = 6.66 \approxeq 6.7\)
The median is the average of the 25th and 26th position = 6.
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