```r
data_means <- list()
for (i in 1:length(loop_data)) {
  data_means <- c(
    data_means,
    mean(loop_data[[i]])
  )
}

str(data_means)
```

```
## List of 4
##  $ : num -0.383
##  $ : num 0.417
##  $ : num 0.855
##  $ : num -20.9
```