Answer:
We accept H₀ we agree with manufacturer´s claim
Step-by-step explanation:
We have a test of proportion
Hypothesis test:
We need to develop a one tail test (left) two determine if we get evidence that the effectiveness of the new medication is less than 65 %
1.-) Test Hypothesis
Null Hypothesis H₀ p = 65 %
Alternative Hypothesis Hₐ p < 65 %
2.-
Confidence interval and z(c)
Confidence interval is 95 % or 0,95 then α = 0,05
and from z tables we see that z(c) = - 1.64
3.-We compute z(p)
z(p) = p - p₀ / √ P₀*Q₀ /n (1)
p = 115/180 = 63,89 % = 0,6389
P₀ = 65 % then Q₀ = 35 % and n = 180
Plugging these values in equation (1) we get
z(p) = ( 0,6389 - 65 )/ √(0,65)*(0,35)/180
z(p) = - 0,0111/ √0,001264
z(p) = - 0,0111/0,0356
z(p) = - 0,3118
4.- We compare z(c) and z(p)
z(c) 0 -1,64 and z(p) = - 0,3118
We see z(p) > z(c) then z(p) is in the acceptance region we accept H₀ we don´t have evidence to say that the effectivness of the medication is lower than a claim of the manufacturer