```r
group_by(zion_srtm_values, ID) %>% 
  summarize_at(vars(srtm), list(~min, ~mean, ~max))
#> # A tibble: 1 x 4
#>      ID   min  mean   max
#>   <dbl> <dbl> <dbl> <dbl>
#> 1     1  1122 1818.  2661
```