To monitor the number of blemishes on a polished surface a company randomly selects 10 units of output from its process and counts the number of blemishes on each unit.The sample results are shown below

Given the sample information above,the standard deviation of the number of defects for this process would be
A)16
B)10
C)4

Question

To monitor the number of blemishes on a polished surface a company randomly selects 10 units of output from its process and counts the number of blemishes on each unit.The sample results are shown below

Given the sample information above,the standard deviation of the number of defects for this process would be

Given the sample information above,the standard deviation of the number of defects for this process would be
A)16 
B)10 
C)4

Quizplus · Accepted Answer

To calculate the standard deviation, we need to first find the mean of the sample.

Mean = (11+6+4+8+3+7+1+5+2+9)/10 = 5.6

Then, we can calculate the deviation of each value from the mean:

(11-5.6), (6-5.6), (4-5.6), (8-5.6), (3-5.6), (7-5.6), (1-5.6), (5-5.6), (2-5.6), (9-5.6)

5.4, 0.6, -1.6, 2.4, -2.6, 1.4, -4.6, -0.6, -3.6, 3.4

Then, we square each deviation:

29.16, 0.36, 2.56, 5.76, 6.76, 1.96, 21.16, 0.36, 12.96, 11.56

We add up these values:

82.32

And divide by (n-1):

82.32/9 = 9.14

Finally, we take the square root:

sqrt(9.14) ≈ 3.02

Therefore, the standard deviation of the number of defects for this process would be approximately 3.02, which corresponds to answer choice (C)

To Monitor the Number of Blemishes on a Polished Surface