? Steve has 7 biscuits in a tin. There are 3 digestive and 4 chocolate biscuits. Steve takes two biscuits at random from the tin. Work out the probability that he chooses two different types of biscuits.​

Respuesta :

Using the hypergeometric distribution, it is found that there is a 0.5714 = 57.14% probability that he chooses two different types of biscuits.​

What is the hypergeometric distribution formula?

The formula is:

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}[/tex]

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

The parameters are:

  • x is the number of successes.
  • N is the size of the population.
  • n is the size of the sample.
  • k is the total number of desired outcomes.

In this problem, the values of the parameters are given as follows:

N = 7, k = 3, n = 2.

The probability that he chooses two different types of biscuits is P(X = 1), hence:

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}C_{N-k,n-x}}{C_{N,n}}[/tex]

[tex]P(X = 1) = h(1,7,2,3) = \frac{C_{3,1}C_{4,1}}{C_{7,2}} = 0.5714[/tex]

More can be learned about the hypergeometric distribution at https://brainly.com/question/24826394

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