An urn contains 5 white and 3 black balls. Two balls are drawn at random without replacement. If X denotes the number of white balls, then find the probability distribution of X.

Respuesta :

Answer:

Generally the probability distribution of the number of white balls (X) is

       X             0                         1                   2

       P(X)        0.35714           0.5357         0.10714

Step-by-step explanation:

From the question we are told that

 The number of white balls is  [tex]N_w = 5[/tex]

  The number of black balls is  [tex]N_b = 3[/tex]

Generally the total number of balls the urn contains is

     [tex]N_t = N_w + N_b = 5 + 3 = 8 \ balls[/tex]

Generally the probability that of the two balls drawn that the balls are  2 white balls and  0 black balls is

     [tex]P( 2_w \ , 0_b) = \frac{ ^{N_w} C _2 * ^{N_b} C _0 }{^{N_t} C_2}[/tex]

Here C stands for combination hence we would be making use of the combination feature in our calculator

=> [tex]P( 2_w \ , 0_b) = \frac{ ^5 C _2 * ^3 C _0 }{^{8} C_2}[/tex]

=> [tex]P( 2_w \ , 0_b) = 0.10714[/tex]

Generally the probability that of the two balls drawn that the balls are  1 white balls and  1 black balls is

     [tex]P( 1_w \ , 1_b) = \frac{ ^{N_w} C _1 * ^{N_b} C _1 }{^{N_t} C_2}[/tex]

=> [tex]P( 1_w \ , 1_b) = \frac{ ^5 C _1 * ^3 C _1 }{^{8} C_2}[/tex]

=> [tex]P( 1_w \ , 1_b) = 0.5357[/tex]

Generally the probability that of the two balls drawn that the balls are  0 white balls and  2 black balls is

     [tex]P( 0_w \ , 2_b) = \frac{ ^{N_w} C _0 * ^{N_b} C _2}{^{N_t} C_2}[/tex]

=> [tex]P( 0_w \ , 2_b) = \frac{ ^5 C _0 * ^3 C _2 }{^{8} C_2}[/tex]

=> [tex]P( 0_w \ , 2_b) = 0.35714[/tex]

Generally the probability distribution of the number of white balls (X) is

       X             0                         1                   2

       P(X)        0.35714           0.5357         0.10714

   

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