In case you guys haven't seen, the Mega Millions currently has a jackpot of $476 Million, which is really a cash option of $341.1 Million.
The odds and payouts are
here
Now, if I'm not mistaken the way we calculate this is take the payouts over the odds as fractions and add them up, yes?
E= 2/74 + 3/140 + 10/843 + 7/346 + 150/13781 + 150/15312 + 10,000/689,064 + 250,000/3,904,700 + 341,400,000/175,711,536
Look good?
If I do my math right, before the jackpot (ie the part that never changes) a ticket appears to have an expectation of about 18 cents (E=.0.1798).
Currently, a ticket is worth about $2.12 (E=2.1228) making the ticket a screaming buy! Looking at this another way, if you would buy all 175M+ combinations you'd more than double your money!
Also, the breakeven point on the Mega Millions is when: (1-0.1798) = (X/175,711,536) the cash jackpot option equals $144,118,601
Did I make any errors?
*this all ignores the effect of splits and taxes