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Confidence interval for a mean

Source: R/statpsych1.R
ci.mean.Rd

Computes a confidence interval for a population mean using the estimated mean, estimated standard deviation, and sample size. Use the t.test function for raw data input.

For more details, see Section 1.7 of Bonett (2021, Volume 1)

Usage

ci.mean(alpha, m, sd, n)

Arguments

alpha

alpha level for 1-alpha confidence

m

estimated mean

sd

estimated standard deviation

n

sample size

Value

Returns a 1-row matrix. The columns are:

  • Estimate - estimated mean

  • SE - standard error

  • LL - lower limit of the confidence interval

  • UL - upper limit of the confidence interval

References

Snedecor GW, Cochran WG (1989). Statistical Methods, 8th edition. ISU University Pres, Ames, Iowa.

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

Examples

ci.mean(.05, 38.3, 8.14, 10)
#>  Estimate       SE       LL       UL
#>      38.3 2.574094 32.47699 44.12301

# Should return:
# Estimate        SE       LL       UL
#     38.3  2.574094 32.47699 44.12301