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%