Standard Deviation
- considered as special form of measures of dispersion that involves all the individual scores/values of the items in the distribution rather than through extremes scores.
formula:
Standard Deviation for Ungrouped Data:
standard deviation= summation of the square of the difference bet. individual scores and the mean divided by the total number of scores minus 1.
mathematically:
S=√∑(x-mean)^2
√n-1
where:
x= individual score
n=total # of scores
For Grouped Data:
standard deviation= summation of the product of the frequency and square of the difference bet. individual scores and the mean divided by the total number of scores minus 1.
Mathematically:
S=√∑f(x-mean)^2
√n-1
where:
x= individual score
n=total # of scores
f=frequency of the table
