I can do basic probability calculations

In my RSS feed reading today was a pointer to a site that administers a brief quiz of your ability to quantify probabilities:

http://www.riskliteracy.org/dnn/

I took it and got this gratifying summary of my results:

Congratulations on completing your statistical and risk literacy test!

Your numeracy score is better than about 75-100% of all college educated individuals. Roughly, this means that out of every 100 people who take the test, you will do better than about 90% (90 people) of all other people. This is the highest score one can receive on this test.

Technically, relative to the general population, you are among the most statistically literate in the world.
Based on your score, you are not very likely to experience the extreme difficulty most people have when faced with common types of statistical thinking. However, you should still take care and may want to double check your calculations or seek additional advice when it comes to important decisions involving risk and statistics (e.g., some medical decisions, financial investment, taking consumer debt).

In our uncertain and complex world you are likely to find that your higher levels of risk and statistical literacy are very beneficial and important.

Indeed, your levels of numeracy reflect a skill level that very few people ever achieve… one that is the result of considerable practice.

As the saying goes: " Practice makes perfect."