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Sample size for a second-stage confidence interval

Source: R/statpsych1.R
size.ci.second.Rd

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

Bonett DG (2021). Statistical Methods for Psychologists https://dgbonett.sites.ucsc.edu/.

Examples

size.ci.second(25, 4.38, 2.0)
#>  Second-stage sample size
#>                        95

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