# notation question

#### kathy678

##### New Member
I work with gifted elementary students and have received help from this forum before.

We purchased a workbook that uses colons when representing probabilities. For example, this workbook says that the probability of getting heads when flipping a coin is 1:2.

Is it okay to use the colon in this situation? My first reaction was that was not correct. It reminds me of odds, or 1 option for the first outcome and two options for the second outcome so a total of three outcomes.

What do you think? Would greatly appreciate your input.

Thank you.

#### hobglobin

##### New Member
kathy678 said:
I work with gifted elementary students and have received help from this forum before.

We purchased a workbook that uses colons when representing probabilities. For example, this workbook says that the probability of getting heads when flipping a coin is 1:2.

Is it okay to use the colon in this situation? My first reaction was that was not correct. It reminds me of odds, or 1 option for the first outcome and two options for the second outcome so a total of three outcomes.

What do you think? Would greatly appreciate your input.

Thank you.
Hi,

I hate working with probabiloties. But: the probability to get head is P=0.5 (if you are flipping nearly infinte times), i.e. 1/2, so colons seem for me somewhat wrong. Odds are used with colons, they are defined as odds= P/(1-P). In your case odds are 1. Nevertheless around P= 0.1 odds and probabilities are very similar.