size.ci.second: Sample size for a second-stage confidence interval

In statpsych: Statistical Methods for Psychologists

Sample size for a second-stage confidence interval

Description

Computes the second-stage sample size required to obtain desired confidence interval precision. This function can use either the total sample size for all groups in the first stage sample or a single group sample size in the first stage sample. If the total first-stage sample size is given, then the function computes the total sample size required in the second-stage sample. If a single group first-stage sample size is given, then the function computes the single-group sample size required in the second-stage sample. The second-stage sample is combined with the first-stage sample to obtain the desired confidence interval width.

For more details, see Section 1.30 of Bonett (2021, Volume 1)

Usage

size.ci.second(n0, w0, w)

Arguments

n0	first-stage sample size
w0	confidence interval width in first-stage sample
w	desired confidence interval width

Value

Returns the required sample size for the second-stage sample

References

\insertRef

Bonett2021statpsych

Examples

size.ci.second(25, 4.38, 2.0)

# Should return:
# Second-stage sample size
#                       95
 

statpsych documentation built on Jan. 13, 2026, 1:07 a.m.