We cannot reproduce your results. There seem to errors in the use of our software.
Here is the code we used:
C#
double[] testdata = {6.64,6.47,5.74,6.66,6.66,6.74,6.65,7.02,6.09,6.2,6.09,6.26,6.36,7.27,
6.44,6.9,6.23,6.2,6.62,6.52,6.1,6.94,6.66,6.86,6.69,6.17,6.57,6.3,6.08,6.27};
double std = SPCArrayStatistics.GetStandardDeviation(testdata);
double mean = SPCArrayStatistics.GetMean(testdata);
VB
Dim testdata() As Double = {6.64, 6.47, 5.74, 6.66, 6.66, 6.74, 6.65, 7.02, 6.09, 6.2, 6.09, 6.26, 6.36, 7.27, _
6.44, 6.9, 6.23, 6.2, 6.62, 6.52, 6.1, 6.94, 6.66, 6.86, 6.69, 6.17, 6.57, 6.3, 6.08, 6.27}
Dim std As Double = SPCArrayStatistics.GetStandardDeviation(testdata)
Dim mean As Double = SPCArrayStatistics.GetMean(testdata)
The standard deviation returns 0.34005. Excel returns 0.34005
The mean returns 6.48. Excel returns 6.48
Double check your methodology. Perhaps you are using VB and did not size your array correctly
Below is a simple copy of the Excel worksheet
6.64 STD 0.340050706
6.47
5.74 Mean 6.48
6.66
6.66
6.74
6.65
7.02
6.09
6.2
6.09
6.26
6.36
7.27
6.44
6.9
6.23
6.2
6.62
6.52
6.1
6.94
6.66
6.86
6.69
6.17
6.57
6.3
6.08
6.27
Standard Deviation question...
Posted - 10 Apr 2008 : 22:33:25
