se2n {BayesRepDesign}

R Documentation

Sample size related to standard error and unit standard deviation

Description

This function computes the sample size related to a specified standard error \sigma and unit standard deviation unitSD, which is the standard deviation of one effective unit (one measurement, one pair of measurements, one event, etc.). The relationship \sigma = \code{unitSD}/\sqrt{n} is assumed. The unit standard deviation depends on the parameter type and the assumptions underlying the standard error calculation. The default is unitSD = 2 which is, under some assumptions, a reasonable approximation to the unit standard deviation for standardized mean differences and log odds/hazard/rate ratios, see Section 2.4 in Spiegelhalter et al. (2004).

Usage

se2n(se, unitSD = 2)

Arguments

se	Standard error
unitSD	Unit standard deviation. Defaults to 2

Value

The sample size corresponding to the specified standard error and unit standard deviation

Author(s)

Samuel Pawel

References

Pawel, S., Consonni, G., and Held, L. (2022). Bayesian approaches to designing replication studies. arXiv preprint. doi:10.48550/arXiv.2211.02552

Spiegelhalter, D.J., Abrams, K.R., Myles, J.P. (2004). Bayesian approaches to clinical trials and health care evaluation. Wiley. doi:10.1002/0470092602

Examples

smd1 <- 0.3
so1 <- 0.05
dprior <- designPrior(to = smd1, so = so1)
ssd1 <- ssdSig(level = 0.025, dprior = dprior, power = 0.8)
se2n(se = ssd1$sr, unitSD = 2) # required n

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