# Probability surveys

Probability is often based on surveys, because you get a more accurate measure of probability by basing your calculation on a large number of results.

Question

Alex is doing some reporting for his local paper. The subject of his article is 'holidays'.

As part of his report he decides to question $$10$$ of his friends about whether they prefer caravanning or camping holidays. Seven out of $$10$$ say that they prefer caravanning, so Alex writes the headline you can see above.

What is wrong with Alex's method?

Alex has based his probability on a very small survey. This is equivalent to throwing a die $$10$$ times, and getting a $$6$$ nine times by chance, and then stating that the probability of obtaining a $$6$$ is $$\frac{9}{10}$$. To estimate probabilities from the results of surveys, you must gather a large number of results.