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