2. According to the Center for Disease Control, about 1 in 80 children in the U.S. have been diagnosed with autism. Suppose you consider a group of 10 children. Find the probability that: a) None have autism; b) 4 have autism; c) at least 2 has autism.

Respuesta :

Answer: (a) 88.18%

               (b) 0.00000226%

               (c) 10.7%

Step-by-step explanation:

[tex]\text{Have Autism}: \dfrac{1}{80}=0.0125\qquad \text{Don't have Autism}: \dfrac{79}{80}=0.9875[/tex]

a) 0 "Have Autism" and 10 "Don't have Autism"

    (0.0125)⁰ (0.09875)¹⁰ = 0.8818    

                                        = 81.18%

b) 4 "Have Autism" and 6 "Don't have Autism"

    (0.0125)⁴ (0.9875)⁶ = 0.0000000226

                                     = 0.00000226%

                                     

c) 2 (or more) Have Autism and 8 (or less) Don't Have Autism

It is best to find the opposite and subtract from 100%

0 "Have Autism" and 10 "Don't have Autism" = 0.8818 (see part a)

                             or

1 "Have Autism" and 9 "Don't have Autism" = (0.0125)¹ (0.9875)⁹

                                                                        = 0.0112

1 - (0.8818 + 0.0112) = 0.1070

                                 = 10.7%

                           

                                   

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