In the story "A Jury of Her Peers," who are Minnie Wright's peers and why?

Minnie's peers are other women--those who understand the
pressures of having to take whatever the man dishes out, so to speak. Specifically, they
are Martha Hale and Mrs. Peters. 

Martha knew Minnie as a
girl, so she is clearly older than Minnie and is therefore not particularly her peer
because of age.  Mrs. Peters is the Sheriff's wife, a position much higher than that of
Minnie, so she's not really Minnie's peer on a social level.  However, both are women
who understand what happened in this relationship and what happened to Minnie to cause
her to commit such a drastic act of violence against her husband.  That's what makes
them her peers.

Their dilemma in "A Jury of her Peers" is
whether or not to tell what they've observed, which is obviously more of a problem for
the wife of a sheriff than for a fellow farm wife.  What they decide, in their unspoken
jury deliberations, is that the men who are investigating would probably not believe
them, and the men on the jury would probably convict her (without any real understanding
of her circumstances) if they did hear all the evidence.   Thus, Minnie's jury of peers
conducted a trial, and they found her innocent.