Answer:
CI 90 % = [ 0,05 ; 0,16 ]
Step-by-step explanation:
From sample we got
n = 110
x = 21
p = 21/110 = 0.19 then q = 1 - p q = 1 - 0.19 q = 0.81
To create a 90 % confidence Interval, the significance level α = 10 %
α = 0.1 α/2 = 0.05
t(c) for α/2 = 0.05 is from z-table z(c) = 1.64
CI 90 % = ( p ± z(c) * √(p*q)/n
CI 90 % = [ 0,11 ± 1.64 * √ (0.19*0.81)/110 ]
CI 90 % = [ 0.11 ± 1.64 * 0.037 ]
CI 90 % = [ 0.11 ± 0,06 ]
CI 90 % = [ 0,05 ; 0,16 ]
