sum of deviations from mean not coming out to be 0 with code-

```
np.sum(arr - np.mean(arr))
It gives answer as -1.7008616737257398e-12
```

sum of deviations from mean not coming out to be 0 with code-

```
np.sum(arr - np.mean(arr))
It gives answer as -1.7008616737257398e-12
```

Hi @priyanka,

Is it a 1D array?

If not can you please make sure that you’re summing up over correct axis?

If yes, can you share the values inside this array?

It a ID array only.

```
arr = np.random.rand(100000)
np.sum(arr - np.mean(arr))
-6.617817405185633e-12
```

ok so in next video sir explains that sum of mean might not come out of 0 due to truncation issues.

@priyanka

e-12 means 10^-12

Above number is basically: `0.000000000006167..`

which can be safely approximated to 0 (a common practise in floating point arithmetic).

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