First let's review the notion of mean, median and mode.
Mean : average number of a number set
Median: the middle number of a number set
Mode: the most repeated number
Then the novel stuff begins!
Measures of dispersion (with mean m)
Variance = ((x1-m)^2 +(x2-m)^2+...+ (xn-m)^2)/n
Standard deviation= variance ^(1/2)
Quartile:( with median m)
Lower: median of the numbers that occur before m
Upper: median of the numbers that occur after m
Example:
42,62,40,29,32,70
Mean =(42+62+40+29+32+70)/6=45.8
Median= 41
Mode= N/A
Variance= (42-45.8)^2+ (62-45.8)^2+...+ (70-45.8)^2/6= 228
Standard deviation= 15.104
Is that hard for you???
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