mean cutted back and categories grouping

Hi ,
I have a problem, I have a lot of data of this :

 preparation
# A tibble: 76 x 7
`Article Code` `Article Libellé court` `N° Commande` CA MBGR Qté PUHT
<dbl> <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
1 2001909 MODULE DEPORT BUS X 250M 4014737794 721 66 1 721
2 2001952 6 ANALOG IN, 4 OUT 8 DIG 4015466742 925 129 1 925
3 2002586 TSX 3705 CA 4014253122 436 28 1 436
4 2003239 COLONNES LUMINEUSES 40 MM 4015900476 397 157 4 99
5 2005078 CONT 9A 1F 1O 220V BC LPL 4014469083 47 14 1 47
6 2005307 CONT 115A 4P 230V 50 60HZ 4014179039 1701 170 6 283
7 2005307 CONT 115A 4P 230V 50 60HZ 4014193057 567 57 2 283
8 2005307 CONT 115A 4P 230V 50 60HZ 4014244859 297 30 1 297
9 2005307 CONT 115A 4P 230V 50 60HZ 4014413626 283 23 1 283
10 2005307 CONT 115A 4P 230V 50 60HZ 4014413736 241 14 1 241
# ... with 66 more rows

I have to make a mean for each code article but I have to keep only important values (classification which are many same prices for each code article).
I don't know to do this....
It me advice to use function mean with option trim and use function cut. But I don't know, I don't suceed.
Thanks you to help me