ci.mean1 {statpsych}

Confidence interval for a single mean

Description

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.

Usage

ci.mean1(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.

Examples

ci.mean1(.05, 24.5, 3.65, 40)

# Should return:
# Estimate        SE       LL       UL
#     24.5 0.5771157 23.33267 25.66733