In: Statistics and Probability
A fertility clinic claims a 40% success rate for in-vitro fertilization (IVF). In a study involving 120 women who initiated IVF at the clinic, 39 live births. Is there evidence to reject the clinic’s claim at the 5% level of significance?
Solution :
Given that,
= 40% = 0.40
1 - = 1 - 0.40 = 0.60
n = 120
x = 39
Point estimate = sample proportion = = x / n = 39 / 120 = 0.325
This is a two tailed test.
The null and alternative hypothesis is,
Ho: p 0.40
Ha: p 0.40
The test statistics,
z = ( - ) / (*(1 - ) ) / n
= ( 0.325 - 0.40) / (0.40*0.60) / 120
= -1.677
P-value = 2* P(Z < z)
= 2*P(Z < -1.677)
= 2*0.0468
= 0.0936
The p-value is p = 0.0936, and since p = 0.0936 ≥ 0.05, it is concluded that the null hypothesis is fails to reject.
Conclusion:
It is concluded that the null hypothesis Ho is fails to reject. Therefore, there is not enough evidence to claim that the population proportion p is different than , at the α = 0.05 significance level.