Given information
Given that when the Euro coin was introduced in 2002, two math professors had their statistics students test whether the Belgian one Euro coin was a fair coin. They spun the coin rather than tossing it and found that out of 250 spins, 140 showed a head (event H) while 110 showed a tail (event T). On that basis, they claimed that it is not a fair coin.
The main objective is to use the tree to find the probability of obtaining at least one head.
Step-by-step explanation
From the given data, if the total possible outcomes of the experiment is 250, and the favourable outcomes of getting a head is 140, and the favourable outcomes of getting a tail is 110.
The formula to find the probability of an event A is defined as
Then, the probabilities of getting a head and tails when a coin is tossed once are: