# Binomial Distribution

## Binomial Distribution :

The binomial distribution is a probability distribution that describes the likelihood of a specific number of successes in a given number of independent trials. It is named after the binomial coefficient, which represents the number of ways that a certain number of successes can occur within a given number of trials.
For example, consider the scenario of flipping a fair coin 10 times. The binomial distribution describes the probability that the coin will land on heads a certain number of times. The possible outcomes of this scenario are 0 heads, 1 head, 2 heads, and so on, up to 10 heads.
To calculate the probability of a specific number of successes, we use the binomial formula:
P(x) = (n! / (x! * (n – x)!) * p^x * (1 – p)^(n – x)
Where:
P(x) is the probability of x successes in n trials
n is the total number of trials
x is the number of successes
p is the probability of success in each trial
1 – p is the probability of failure in each trial
In the case of flipping a fair coin 10 times, the probability of flipping heads is 0.5, so the formula becomes:
P(x) = (10! / (x! * (10 – x)!) * 0.5^x * 0.5^(10 – x)
Using this formula, we can calculate the probability of each possible outcome:
P(0) = 0.000976562
P(1) = 0.009765625
P(2) = 0.043945312
P(3) = 0.117187500
P(4) = 0.205078125
P(5) = 0.24609375
P(6) = 0.205078125
P(7) = 0.117187500
P(8) = 0.043945312
P(9) = 0.009765625
P(10) = 0.000976562
The binomial distribution is often represented as a graph, known as a binomial distribution curve. In this case, the curve would show the probability of each possible number of heads in 10 flips. The curve would be symmetrical, with the peak in the middle and the probabilities decreasing as the number of heads deviated from the mean.
Another example of a binomial distribution is the probability of a certain number of customers buying a product in a given number of sales calls. Suppose a salesperson makes 100 sales calls, and the probability of a customer making a purchase is 0.25. The binomial distribution would describe the likelihood of the salesperson making 0 sales, 1 sale, 2 sales, and so on, up to 100 sales.
Using the binomial formula, we can calculate the probability of each possible outcome:
P(0) = 0.00000000000000028819816
P(1) = 0.00000000000028819816
P(2) = 0.00000000005764355328
P(3) = 0.000000005764355328
P(4) = 0.00000028819816
P(5) = 0.00000843454912
P(6) = 0.00018647163
P(7) = 0.00294912064
P(8) = 0.02893853
P(9) = 0.17684625
P(10) = 0.12093235
P(11) = 0.35486064
P(12) = 0.57643553
P(13) = 0.65346901
P(14) = 0.57643553
P(15) = 0.35486064
P(16) = 0.12093235
P(17) = 0.02893853
P(18) = 0.00294912064
P(19) = 0.00018647163
P(20) = 0.00000843454912
P(21) = 0.00000028819816
P(22) = 0.000000005764355328
P(23) = 0.00000000005764355328
P(24) = 0.00000000000028819816
P(25) = 0.00000000000000028819816
The binomial distribution curve for this scenario would show the probability of each possible number of sales in 100 calls. The curve would be skewed to the right, with a higher probability of making a smaller number of sales and a lower probability of making a larger number of sales.
In conclusion, the binomial distribution is a probability distribution that describes the likelihood of a specific number of successes in a given number of independent trials. It is calculated using the binomial formula and is often represented as a binomial distribution curve. The shape of the curve depends on the probability of success in each trial and the total number of trials.