Question 1104853
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With the numbers you show, the standard deviation is 3.055 to 3 decimal places.<br>
If you used the numbers you showed us and got 3.65, then there is something wrong with your calculations.<br>
It seems a bit odd to me that the book says the answer is 3.  I don't work that much with statistics, but I wouldn't think it would be standard practice to round a value for the standard deviation to a whole number.<br>
And that leads me to ask you if you are sure you are using (and showing us) the numbers given in the problem in your book.