R/B/Y IV values?

[Angela]

I knew there were some things like IVs in the first game that made a pokemon's stats different from another's, but I thought they all had the same amount, just for different stats.

However, I tried the Mew trick twice in my Blue version, once with the swimmer in Misty's gym and once with the Slowpoke youngster, and I got a Mew with 19/18/18/19 (maybe not those exactly, but I remember Defense and Speed being weaker than Attack and Special, and weaker than the next Mew), and the next Mew having 20/20/20/21 stats! So are some Pokemon just weaker than others or what?

 

[The Outrage]

Did you use a first/second generation IV calculator? They had lower IVs in the past, but I believe their maximum stats (discluding EVs and obvciously natures) were still the same. They could not have IVs above 15.

And obviously some Pokemon are just weaker than others, even in the same species, that's the whole point of IVs -_-