Probability
Probability is a mathematical and a conceptual measure. Something is considered probable on the basis of known facts and observations.
Probability is not 'odds', like in horse racing. Those odds are based on a more complex relative measure based on past performance. Odds will vary significantly, depending on competitiveness of the field of participants.
Mathematical probability
Mathematical probability is usually based on statistics.
If you flip a single coin, the obvious probability is one side or another, so the probabilities are even for either side.
If you flip two coins, the probabilities for combinations are divided, because of the possibility of heads only, tails only, or a combination of head and tail. So there are three possible combinations. Probability is 1/3 of any combination on any individual throw.
 
If you flip three coins, you get a more complex set of possibilities:
 3 heads
 3 tails
 2 heads 1 tail
 2 tails 1 head
Probability is 1/4 for any combination on any single throw.
Mathematical probabilities are easy to measure, and reliable in terms of assessing the risks of any bet on any combination. If you bet $1 on each of the combinations for 3 coins, you can be certain that 3 of them would be losing bets.
Conceptual probability
Conceptual probability is based on observation of behavior or known facts as a measure of predictability. This is 'philosophical' probability,
If a person is known to like beer, and says they're going to the pub, the probability of that person buying a beer is almost 100%.
If a person is known to like eating fish, and wants to eat out, the probability of going to a seafood restaurant is high.

Conceptual probability is more often used in attempting to understand situations and solve problems.
Why would crops fail in an area traditionally fertile?
Probabilities have to include the facts of crop failure:
 Lack of water
 Lack of nutrients in the soil
 Lack of proper land management
 Planting at the wrong time
 Soil biology problems
 Weather conditions

These factors are used to decide the probable causes of the problem. Conceptual probability is used to analyze quality of probabilities, discarding possibilities until the probable causes are found.