Answer:
Q1 z(s) is in the rejection region for H₀ ; we reject H₀. We can´t support the that means have no difference
Q2 CI 95 % = ( 0,056 ; 0,164 )
Step-by-step explanation:
Sample information for people under 18
n₁ = 500
x₁ = 180
p₁ = 180/ 500 p₁ = 0,36 then q₁ = 1 - p₁ q₁ = 0,64
Sample information for people over 18
n₂ = 600
x₂ = 150
p₂ = 150 / 600 p₂ = 0,25 then q₂ = 1 - p₂ q₂ = 1 - 0,25 q₂ = 0,75
Hypothesis Test
Null hypothesis H₀ p₁ = p₂
Alternative Hypothesis Hₐ p₁ ≠ p₂
The alternative hypothesis indicates that the test is a two-tail test.
We will use the approximation to normal distribution of the binomial distribution according to the sizes of both samples.
Testin at CI = 95 % significance level is α = 5 % α = 0,05 and
α/ 2 = 0,025 z (c) for that α is from z-table:
z(c) = 1,96
To calculate z(s)
z(s) = ( p₁ - p₂ ) / EED
EED = √(p₁*q₁)n₁ + (p₂*q₂)/n₂
EED = √( 0,36*0.64)/500 + (0,25*0,75)/600
EED = √0,00046 + 0,0003125
EED = 0,028
( p₁ - p₂ ) = 0,36 - 0,25 = 0,11
Then
z(s) = 0,11 / 0,028
z(s) = 3,93
Comparing z(s) and z (c) z(s) > z(c)
z(s) is in the rejection region for H₀ ; we reject H₀. We can´t support the idea of equals means
Q2 CI 95 % = ( p₁ - p₂ ) ± z(c) * EED
CI 95% = ( 0,11 ± 1,96 * 0,028 )
CI 95% = ( 0,11 ± 0,054 )
CI 95 % = ( 0,056 ; 0,164 )
