I will win our office football pool this week if the Rams defeat (or tie) the 49ers tonight OR the combined total for both teams tonight is 46 points or more.

Assume the current line is SF -3.5 with an over/under of 44.

Given the above information, what is my estimated probability of winning this week's pool?

(I will give the answer later this afternoon or early this evening, although I'm pretty sure with this crowd, I don't need to. I belong to a couple of other forums and most of those guys are clueless to this sort of thing.)

http://wizardofodds.com/games/sports-betting/nfl/

Depending on how you calculate the chances of winning over 46 when the posted total is 44, your overall chances of winning are around 65.5%

I think the over is a much better bet than the Rams covering. I think the total will go over 50.

Quote:AyecarumbaI get 41.2% on the back of my napkin. Probability of winning the straight bet ~38.6%, Probability of winning the over ~43.8%. Add them up and divide by two = 41.2%

I think the over is a much better bet than the Rams covering. I think the total will go over 50.

This is doing it the wrong way.

You need to take the chances of winning the straight bet = 38.6%. Chance of not winning: 100 - 38.6 = 61.4%

Chances of winning the over = 43.8% Chance of not winning: 100-43.8% = 56.2%

Chances of not winning either are .562 * .614 = 0.345068

1 - 0.345068 = 0.654932

OVERALL CHANCES OF WINNING OFFICE POOL = 65.4932%

Quote:sodawaterThis is doing it the wrong way.

You need to take the chances of winning the straight bet = 38.6%. Chance of not winning: 100 - 38.6 = 61.4%

Chances of winning the over = 43.8% Chance of not winning: 100-43.8% = 56.2%

Chances of not winning either are .562 * .614 = 0.345068

1 - 0.345068 = 0.654932

OVERALL CHANCES OF WINNING OFFICE POOL = 65.4932%

Ding Ding Ding. We have a winner. Good work. (I calculated them to be almost 66%.)

So far, over 418 members have read my post in that other forum, and they still haven't gotten it right!

Quote:EdCollinsDing Ding Ding. We have a winner. Good work. (I calculated them to be almost 66%.)

So far, over 418 members have read my post in that other forum, and they still haven't gotten it right!

Yeah, assuming no effect of correlation. I can't decide which way the correlation goes in my head, so just say it's 0

I agreeQuote:sodawaterYou need to take the chances of winning the straight bet = 38.6%.

Chances of winning the over = 43.8%

I will do this another way from Counting 101 - Inclusion/Exclusion

we can first add the probabilities but do not divide by 2 as was done earlier

= 38.6% + 43.8% - (38.6% * 43.8%)

try it (I know you will)

math is fun!

same concept as rolling at least one 6

with 2 6-sided dice

1/6 + 1/6 - (1/6 * 1/6) because we can get both 6,6 and we already counted them once

(so we subtract their union)

2/6 - 1/36 = 12/36 - 1/36 = 11/36

If they can happen at the same time (the OP example of he wins the game and wins the over)

we have to subtract out that probability of both happening

of course 1-(5/6)^2

this Inclusion/Exclusion method works well for more complex problems too

Sally

Did anyone confirm that the probabilities I used were appropriate?