Questions for Don S. - Variance and Avg.

Don,

Suppose someone receives $1500 if a fair coin comes up heads and loses $500 if it lands tails. EV is $500/toss. What is the variance per toss and how do you calculate it? If it is not too much trouble please walk me through it.

My other question pertains to average win and loss in blackjack. Is there a method to estimate average win/loss for a counter given his hourly EV, SD, and Variance? Thanks for any answers.

MJ