What characters are more common in my MD2 hash?
Mathematica, 43 bytes
Tr@Sign[15-2#~Hash~"MD2"~IntegerDigits~16]&
Outputs the number of digits in 01234567 minus the number of digits in 89abcdef.
JavaScript (ES6), 731 bytes
This monster is implementing the MD2 algorithm, so it's embarrassingly long. Based on js-md2 by Chen Yi-Cyuan.
let f =
m=>{L=x=s=b=0,n=m.length,M=[],X=[],C=[],S=[...atob`KS5DyaLYfAE9NlSh7PAGE2KnBfPAx3OMmJMr2bxMgsoem1c8/dTgFmdCbxiKF+USvk7E1tqe3kmg+/WOuy/ueqloeZEVsgc/lMIQiQsiXyGAf12aWpAyJzU+zOe/95cD/xkws0iltdHXXpIqrFaqxk+4ONKWpH22dvxr4px0BPFFnXBZZHGHIIZbz2XmLagCG2Alra6wufYcRmFpNEB+D1VHoyPdUa86w1z5zrrF6iYsUw1uhSiECdPfzfRBgU1Satw3yGzBq/ok4XsIDL2xSniIlYvjY+ht6cvV/jsAHTny77cOZljQ5KZ3cvjrdUsKMURQtI/tHxrbmY0znxGDFA`].map(c=>c[O='charCodeAt']());for(l=1;l-2;){for(j=19;j--;)M[j]=M[16+j]||0;for(i=s;i<16;x++)L=(x-n||(b+=i-s,s=i-16,l=2),C[i]^=S[(M[i++]=x<n?m[O](x):16-(b&15))^L]);for(i=0;i<l;i++){for(j=16;j--;)X[32+j]=(X[16+j]=(i?C:M)[j])^X[j];for(t=j=0;j<18;t=t+j++&255)for(k=0;k<48;)t=X[k++]^=S[t]}}for(i=16,n=-i;i--;)n+=!(X[i]&8)+!(X[i]&128);return n}
console.log(f(''))
console.log(f('The quick brown fox jumps over the lazy cog'))
console.log(f('m'))Python 2 + Crypto, 108 99 93 91 87 78 bytes
Python doesn't have a native builtin for MD2.
from Crypto.Hash import*
lambda s:sum(x<'8'for x in MD2.new(s).hexdigest())-16
Saved 12 bytes thanks to @ovs.
Saved 9 bytes thanks to @FelipeNardiBatista.