Correction
 

I just noticed that my conversion of percentage to odds were all off by 1. Here's a corrected version:

The odds for exactly 7 and exactly 3 are the same:

C(10,7)/2^10 = C(10,3)/2^10 = 11.7% or 7.5-1


For the odds of 7 or more, it is easiest to use the BINOMDIST function in Excel:

1 - BINOMDIST(6,10,0.5,TRUE) = 17.2% or 4.8-1

That is 1 minus the odds of 0,1,2,..6. If you don't have Excel, this is the same as:

[ C(10,7) + C(10,8) + C(10,9) + C(10,10) ] / 2^10 = 17.2% or 4.8-1

where we have just added the probabilities for 7,8,9,10.


Same thing for 3 or more:

1 - BINOMDIST(2,10,0.5,TRUE) = 94.5% or 0.06-1

In this case it's easiest to take 1 minus the probability of 0,1,2:

1 - [ C(10,0) + C(10,1) + C(10,2) ] / 2^10 = 94.5% or 0.06-1