In: Statistics and Probability
In a Phase II clinical trial with a binary endpoint, 8 out of 20 patients responded to a new drug. Let X be the total number of patients responding to the new drug among the 20 patients and pi be the population response rate. Please specify the distribution of X and obtain a 95% confidence interval for pi.
Solution :
Given that,
Point estimate = sample proportion = = x / n = 8 / 20 = 0.4
1 - = 1 - 0.4 = 0.6
Z/2 = 1.96
Margin of error = E = Z / 2 * (( * (1 - )) / n)
= 1.96 * (((0.4 * 0.6) / 20)
= 0.215
A 95% confidence interval for population proportion p is ,
- E < < + E
0.4 - 0.215 < < 0.4 + 0.215
0.185 < < 0.615
The 95% confidence interval for the population proportion is : 0.185 , 0.615