Answer :
Using the binomial distribution, it is found that there is a 0.125 = 12.5% probability of observing exactly 3 tails.
What is the binomial distribution formula?
The formula is:
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
In this problem, considering 3 tosses of a fair coin, the parameters are n = 3 and p = 0.5.
The probability of 3 tails is P(X = 3), hence:
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 3) = C_{3,3}.(0.5)^{3}.(0.5)^{0} = 0.125[/tex]
0.125 = 12.5% probability of observing exactly 3 tails.
More can be learned about the binomial distribution at https://brainly.com/question/24863377