# Calculate Standard deviation in table

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Dion Theunissen on 25 Jun 2021
Answered: Erkan MSN on 24 Jan 2022
Hi,
I have a table with 20 columns, I want to make a new column with the standard deviation of each row from column 4 to 6.
So after column 6 i want to have a column with the stdev of all rows of column 4:6.
How can I do that?

Chunru on 25 Jun 2021
a = array2table(rand(5,8)) % Sample table
a = 5×8 table
Var1 Var2 Var3 Var4 Var5 Var6 Var7 Var8 _______ _______ _______ _________ _______ _________ _______ _______ 0.4022 0.9627 0.53548 0.35205 0.70636 0.89738 0.50393 0.44203 0.96785 0.33289 0.57833 0.36493 0.84985 0.0031283 0.34461 0.3312 0.29543 0.18861 0.91065 0.025623 0.40162 0.88419 0.24007 0.38235 0.66403 0.19131 0.24685 0.0092594 0.10672 0.51052 0.79236 0.43115 0.62483 0.95579 0.37075 0.11087 0.65024 0.55079 0.97985 0.57458
s = std(a{:, 4:6}, [], 2) % std along rows (dim=2)
s = 5×1
0.2767 0.4249 0.4304 0.2658 0.2870
b = [a table(s, 'VariableNames', {'std'})] % combine with original
b = 5×9 table
Var1 Var2 Var3 Var4 Var5 Var6 Var7 Var8 std _______ _______ _______ _________ _______ _________ _______ _______ _______ 0.4022 0.9627 0.53548 0.35205 0.70636 0.89738 0.50393 0.44203 0.27671 0.96785 0.33289 0.57833 0.36493 0.84985 0.0031283 0.34461 0.3312 0.42485 0.29543 0.18861 0.91065 0.025623 0.40162 0.88419 0.24007 0.38235 0.43038 0.66403 0.19131 0.24685 0.0092594 0.10672 0.51052 0.79236 0.43115 0.26577 0.62483 0.95579 0.37075 0.11087 0.65024 0.55079 0.97985 0.57458 0.28704
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Dion Theunissen on 25 Jun 2021
Thanks!

### More Answers (1)

Erkan MSN on 24 Jan 2022
If you want to calculate the standard deviation of the whole table:
For example "cax" is table.
1.6424 5.2601 1.4691 0.7361 0.2771
1.0531 0.5722 1.8804 4.9636 0.9451
1.8084 1.6537 1.5916 0.8352 0.7740
0.7550 1.4221 1.7003 2.5646 0.4272
2.2935 2.5158 0.7656 1.0110 2.0810
1.0765 0.5390 1.9687 2.0829 0.4572
1.0493 1.4736 1.2810 1.0911 0.2073
2.1630 0.5679 2.8582 1.6006 0.4746
1.1625 0.7333 0.2623 0.6887 0.7897
2.9148 0.2886 3.1662 0.3645 0.5730
std(cax,[],'all')
ans =
1.0786e+03

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