Answer:
Step-by-step explanation:
Here X the no of children suffering from hookworm treated and recovered is binomial because
a) Each child is independent of the other
b) There are only two outcomes
c) The probability for any child to recover is constant as 90% = 0.9
X is Bin (20,0.9)
a) Prob that all 20 will be cured
=P(X=20)=[tex]0.9^{20} \\=0.1216[/tex]
b) Prob all but 1 will be cured=[tex]P(x=1) = 20C1 (0.9) (.1)^{19} \\=1.8(10^8)[/tex]
c) Prob exactly 18 will be cured
[tex]=P(X=18)\\=20C18 (0.9)^{18} (0.1)^2\\= 0.2852[/tex]
d) Prob exactly 90% will be cured.
=[tex]P(X=18)\\=20C18 (0.9)^{18} (0.1)^2\\= 0.2852[/tex]
