Bernoulli Trial :
A Bernoulli trial is a random experiment that has only two possible outcomes, typically referred to as “success” and “failure.” The probability of success and failure is constant for each trial, and the outcome of each trial is independent of the others.
For example, consider flipping a coin. There are only two possible outcomes, heads or tails, and each outcome has a probability of 0.5. Every time the coin is flipped, the probability of either outcome remains the same, and the outcome of the current flip does not affect the outcome of future flips. This is a Bernoulli trial.
Another example is the toss of a single die. There are six possible outcomes, and each outcome has a probability of 1/6. The probability of rolling a certain number does not change, and the outcome of each toss does not affect future tosses. This is also a Bernoulli trial.
Bernoulli trials can be used to model a wide range of real-life situations, such as medical trials, election polls, and gambling games. In a medical trial, for instance, the success outcome could represent a positive response to a treatment, while the failure outcome could represent no response or a negative response. In an election poll, the success outcome could represent a vote for a particular candidate, while the failure outcome could represent a vote for another candidate or no vote at all. In a gambling game, the success outcome could represent a win, while the failure outcome could represent a loss.
One important concept in Bernoulli trials is the expected value, which is the average value of the outcomes over a large number of trials. For example, in the coin flip example, the expected value of the number of heads is 0.5, because the probability of flipping heads is 0.5 and the probability of flipping tails is also 0.5. Similarly, in the dice toss example, the expected value of the number of sixes is 1/6, because the probability of rolling a six is 1/6.
Another important concept in Bernoulli trials is the binomial distribution, which describes the probability of a certain number of successes in a given number of trials. For example, consider flipping a coin 10 times. The binomial distribution describes the probability of flipping a certain number of heads in those 10 flips. For instance, the probability of flipping exactly 5 heads is 0.246, the probability of flipping exactly 6 heads is 0.117, and so on.
One important property of the binomial distribution is that it becomes closer to a normal distribution as the number of trials increases. This property is known as the central limit theorem, and it is important in many fields, such as statistics and economics.
In summary, a Bernoulli trial is a random experiment with two possible outcomes, success and failure, where the probability of each outcome remains constant for each trial and the outcome of each trial is independent of the others. Bernoulli trials can be used to model a wide range of real-life situations, and they have important concepts such as the expected value and the binomial distribution.