range is the difference between the lowest and the highest.
the number are:
76,91,95,95,99
put them in order to get:
76, 91, 95, 95, 99
the range would be 99 minus 76 = 23
variance is the sum of the squared differences from the mean divided by the number of entries.
the mean is the average.
76 + 91 + 95 + 95 + 99 = 456 / 5 = 91.2
the variance is calculated as shown in the following table
c1 c2 c3
-------------------------
76 -15.2 231.04
91 -0.2 0.04
95 3.8 14.44
95 3.8 14.44
99 7.8 60.84
--------------------------
456 320.8 total
91.2 64.16 average (total divided by 5)
the first column is the data
the sum of the data is 456
the mean (average) of the data is 91.2
the second column is the difference between each data item and the mean.
the fact that the number is negative doesn't matter because it will be squared and become positive.
the third column is the square of the difference.
the sum of the squared difference is 320.8
the mean (average) of the squared difference is 64.16
64.16 is your variance
91.2 is your mean
23 is your range