Sharp el-9950

142
Chapter 7: List Features
7 stdDv( stdDv(list [, frequency list])
Returnsthestandarddeviationofthespeciedlistitems.
Example
• Calculatethestandard
deviation using the list items of
listL2.
Note: If relative frequencies or
probabilities are stored in the
frequencylist,pleaseuseP_stdDv.
8 varian( varian(list [, frequency list])
Returnsthevarianceofthespeciedlistitems.
Example
• Calculatethevarianceusing
thelistitemsoflistL2.
9 P_stdDv( P_stdDv(list [, frequency list])
Returnsthepopulationstandarddeviationofthespeciedlistitems.
Example
• Calculatethepopulation
standard deviation using the
listitemsoflistL2.
Standard deviation and variance
Standard deviation: s =
Variance =
Population standard deviation: σ=
where n = number of list items
lk = list item value
m = mean value of the list
(Estimation)
(Estimation)
(Variance in case of complete survey)
Variance
n
– 1
(l
k – m)
2
Σ
k = 1
n
n
(l
k – m)
2
Σ
k = 1
n