I want to calculate the distribution of NA per row and per column of my data.frame. Shouldn't the average be the same? Although the difference is very small, I do not understand why it exists.

```
apply(base, 1, function(x) round(sum(is.na(x)/length(x)),2)) %>%
as.vector() %>%
summary()
Min. 1st Qu. Median Mean 3rd Qu. Max.
0,0700 0,2000 0,2300 0,2141 0,2300 0,2800
```

```
apply(base, 2, function(x) round(sum(is.na(x)/length(x)),2)) %>%
as.vector() %>%
summary()
Min. 1st Qu. Median Mean 3rd Qu. Max.
0,0000 0,0000 0,0000 0,2136 0,0550 1,0000
```