You flip a coin 4 times that has been weighted such that heads comes up twice as often as tails . What is the probability that all 4 of them are heads?

Respuesta :

Answer:

0.1975

Step-by-step explanation:

Let the probability of getting heads on flipping the coin = p

Then the probability of getting tails on flipping the coin = 1-p

It is given that probability of heads is twice the probability of tails.

[tex]\[p= 2* (1-p)\][/tex]

[tex]\[=> p= 2 - 2p\][/tex]

[tex]\[=> 3p= 2 \][/tex]

[tex]\[=> p= \frac{2}{3} \][/tex]

So that probability of getting a head on single coin flip = [tex]\[\frac{2}{3}\][/tex]

This means that the probability of getting heads on 4 coin flips =

[tex]\[ p^{4} \][/tex]

[tex]\[= (\frac{2}{3})^{4} \][/tex]

[tex]\[= 0.1975 \][/tex]

Probability of an event is the measure of its chance of occurrence. The probability of all 4 tossed coins in given context coming out as heads is 0.197 approximately.

How to find that a given condition can be modeled by binomial distribution?

Binomial distributions consists of n independent Bernoulli trials.

Bernoulli trials are those trials which end up randomly either on success (with probability p) or on failures( with probability 1- p = q (say))

Suppose we have random variable X pertaining binomial distribution with parameters n and p, then it is written as

[tex]X \sim B(n,p)[/tex]

The probability that out of n trials, there'd be x successes is given by

[tex]P(X =x) = \: ^nC_xp^x(1-p)^{n-x}[/tex]

For the given case, let model the condition as:

Success = getting head on given biased coin

Probability of success = p = 2/3 (as head comes twice as often as tails, so probability of heads = twice probability of q = x say,

then 2x + x = 1(total probability is 1), or x = 1/3 = probability of tails,

thus, probability of heads= 2/3)

Failure = getting tail on given biased coin

Probability of failure = q = 1-p = 1-2/3 = 1/3

All coins' results are independent, thus, they are Bernoulli trials.

The count of Bernoulli trials is n = 4

Let random variable X tracks the number of heads obtained on tossing these 4 given biased coins.

Then,

[tex]X \sim B(4,2/3)[/tex]

The needed probability is

P(X = 4)

Using the probability function of binomial distribution, we get:
[tex]P(X = 4) = \: ^4C_4(2/3)^4(1/3)^0 = \dfrac{16}{81} \approx 0.197[/tex]

Thus, The probability of all 4 tossed coins in given context coming out as heads is 0.197 approximately.

Learn more about binomial distribution here:

https://brainly.com/question/13609688