Description Usage Arguments Details Author(s) References
The $z$-based confidence interval is commonly used in
estimating population mean using sample data. It is based
on the Standard Normal distribution. interval_2p
provides tools for calculating and illustrating the sample
size requirement and other design factors associated with
these intervals.
1 2 |
E |
Margin of error for the difference of proportions |
p1 |
Proportion observed in group 1. |
p2 |
Proportion observed in group 2. |
n |
Total sample size for groups 1 and 2. |
n1 |
Sample size for group 1. |
n2 |
Sample size for group 2. |
k |
proportion of the total samples size |
alpha |
Significance level (or 1-confidence) |
This function is currently under development. I needed it for a study design.
This can be useful for designin equivalence trials. According to Schumi and Wittes, “Sometimes, the goal is not to show that the new treatment is better, but that the new treatment is 'equivalent' to the control...At the end of the trial, a CI is computed around the difference between two test statistics (equivalence trials typically use 90 the two treatments are called 'equivalent.'"
Benjamin Nutter
Jennifer Schumi and Janet T Wittes, “ Through the looking glass: understanding non-inferiority," _Trials_, 2011, 12:106.
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