```r
summarise(group_by(filter(starwars, gender == "male"), species), mean(height))
```

```
## # A tibble: 32 x 2
##    species   `mean(height)`
##    <chr>              <dbl>
##  1 Aleena               79 
##  2 Besalisk            198 
##  3 Cerean              198 
##  4 Chagrian            196 
##  5 Dug                 112 
##  6 Ewok                 88 
##  7 Geonosian           183 
##  8 Gungan              209.
##  9 Human                NA 
## 10 Iktotchi            188 
## # ... with 22 more rows
```