I have fwg tabel
Mol% Counts
0.00225 836.95
0.00225 834.69
0.00225 835.18
0.00967 3515.53
0.00967 3513.75
0.00967 3516.45
0.01883 6837.86
0.01883 6834.00
0.01883 6829.18
0.04595 16645.62
0.04595 16658.36
0.04595 16634.59
0.05791 20938.43
0.05791 20939.91
0.05791 20919.43
0.07558 27318.70
0.07558 27337.69
0.07558 27348.80
0.09317 33587.92
0.09317 33598.91
0.09317 33586.73

I enter the linest function as follow to get the third order line
{=LINEST(D2:D22,E2:E22^{1,2,3},,TRUE)}
Excel returns:
3.20132E-17 -1.06333E-12 2.77498E-06 -7.54106E-05 #N/A
1.25454E-17 6.72512E-13 9.69992E-09 3.00599E-05 #N/A
0.999998275 4.6705E-05 #N/A #N/A #N/A
3284344.441 17 #N/A #N/A #N/A
0.021492985 3.70831E-08 #N/A #N/A #N/A

The first row gives the coefficients and the intercept.
The fifth row first column gives the s2SSR (sum of squares regression). So
far I understand OK.

What I am looking for is the sMSE. This figure should be 2.18136*10^-9
(according to an example analytical method).
Where can I find this in the above table that Exel returned? Do I need to do
some more calculations? Or enter another function altogether?

The analytical method I refer to is ISO 6974 part 2 ( analyses of natural gas)