At ABC University, a group of students was selected and asked how much of their weekly allowance they spent in buying mobile phone load. The following is the list of amounts spent: Php 120, 110, 100, 200, 10, 90, 100, 100. find the standard deviation.
Formula for the standart deviation(unbiased): "s^2=\\Sigma (x(i)-u)^2\/(n-1)", where x(i)-element with i number, u-mean of the sample, n-sample size.
Mean of the sample: "u=(120+...+100)\/8=103.75"
Sum:
"\\Sigma (x(i)-u)^2=(120-103.75)^2+...+(100-103.75)^2= 18413.6875"
"s^2=18413.6875\/7=2630.5(approximately)"
standart deviation is equal to s, and approximately equal to 51.3
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