The population size of the above data is 8, that is N=8 The mean (average) = (<span>12 +10+ 11.5 +11.5 +12 +9 +9 +11)/8 = 10.75 Standard deviation is the square root of variance, it is one of the measures of central dispersion, that is a measure of by how much the values in the data set are likely to differ from the mean. In this case, Standard deviation, </span>s= √(∑(x-m)²)/(n-1) = 1.172 Thus, best approximation of the standard deviation is 1.17
5600 can be simplified. Say you were to just take the two zeros off the end and you would have 56. Now divide 56 by 7 and you get 8. Add the zeros back to the 8 and your answer is 7 x 800. Hope this helps.