SOLUTION: Find the standard deviation for the given data. The manager of an electrical supply store measured the diameters of the rolls of wire in the inventory. The diameters of the roll

Algebra ->  Probability-and-statistics -> SOLUTION: Find the standard deviation for the given data. The manager of an electrical supply store measured the diameters of the rolls of wire in the inventory. The diameters of the roll      Log On


   

Question 202195: Find the standard deviation for the given data.
The manager of an electrical supply store measured the diameters of the rolls of wire in the inventory. The diameters of the rolls (in m) are listed below. Round results to four decimal places.
0.202 0.426 0.349 0.365 0.669 0.427 0.569
A) 1.2917
B) 1.4310
C) 0.365
D) 0.1523

I came up with like .141 or something, how do i solve this?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
First sort the numbers into ascending order (from least to greatest):
0.202,0.349,0.365,0.426,0.427,0.569,0.669


Now let's find the mean. So add up all of the numbers and divide the sum by the number of numbers (which in this case is 7).
Mean=%280.202%2B0.349%2B0.365%2B0.426%2B0.427%2B0.569%2B0.669%29%2F7=3.007%2F7=0.42957

So the mean is 0.42957



Use this formula to find the Standard Deviation:

Standard Deviation: where is the average, is the ith number, and is the number of numbers

So we can replace N with 7



Subtract 7-1 to get 6



Replace with 0.42957



Expand the summation (replace each x%5Bi%5D with the respective number)




Subtract the terms in the parenthesis



Square each term



Add up all of the terms

sqrt%28%281%2F6%290.139237%29

Multiply

sqrt%280.0232061666666667%29

Take the square root

0.152335703847347

So the standard deviation is 0.152335703847347


which rounds to 0.1523


So the answer is D) 0.1523