Higher Concepts of Mathematics
STATISTICS
Frequency Distribution
Temperatures
Frequency (f)
(f)(xi)
573
574
575
576
578
2
4
5
3
1
15
1146
2296
2875
1728
578
8623
Then calculate the mean,
x
1
n
n
i 1
xi
x
2(573)
4(574)
5(575)
3(576)
1(578)
15
x
8623
15
x
574.9
Variability
We have discussed the averages and the means of sets of values. While the mean is a useful tool
in describing a characteristic of a set of numbers, sometimes it is valuable to obtain information
about the mean. There is a second number that indicates how representative the mean is of the
data. For example, in the group of numbers, 100, 5, 20, 2, the mean is 31.75. If these data
points represent tank levels for four days, the use of the mean level, 31.75, to make a decision
using tank usage could be misleading because none of the data points was close to the mean.
Rev. 0
Page 5
MA-05
