Question

The manager of a warehouse would like to know how many errors are made when a product’s serial number is read by a bar-code reader. Six samples are collected of the number of scanning errors: 36, 14, 21, 39, 11, and 2 errors, per 1,000 scans each. What is the mean and standard deviation for these six samples?

Answer 1

Mean=20.5

standard deviation=13.28

Explanation:

We are given six samples i.e.

36, 14, 21, 39, 11, and 2

Mean is the average of all the samples

Mean= sum of all samples/no. of samples

Mean=(36+14+21+39+11+2)/6

Mean=20.5

Standard deviation is the positive square root of variance where

variance= sum of square of samples/number of samples-(mean)²

variance=(36²+14²+21²+39²+11²+2²)/6-(20.5)²

= 596.5-420.25

= 176.25

standard deviation= √(176.25)

standard deviation= 13.28