Confidence interval around the mean

Calculates a confidence interval for the mean of a numeric variable (or each numeric variable in a data frame or matrix).

Usage

ciMean(x, conf = 0.95, na.rm = FALSE)

Arguments

x: A numeric vector, matrix, or data frame.
conf: The confidence level. Defaults to 0.95 for a 95% interval.
na.rm: Set to TRUE to remove missing values before computing the interval. Defaults to FALSE.

Value

A matrix with one row per variable and two columns giving the lower and upper bounds of the confidence interval. Column names reflect the confidence level (e.g., "2.5%" and "97.5%" for a 95% interval).

Details

Calculates a confidence interval for the mean under the standard assumption that the data are normally distributed. When x is a matrix or data frame, a separate interval is computed for each column. Non-numeric columns in a data frame produce NA rows in the output.

Examples

x <- c(1, 3, 6)
ciMean(x) # 95% confidence interval
#>        2.5%    97.5%
#> x -2.918276 9.584943
ciMean(x, conf = 0.80) # 80% confidence interval
#>         10%      90%
#> x 0.5935938 6.073073

# for comparison: equivalent result via lm
confint(lm(x ~ 1))
#>                 2.5 %   97.5 %
#> (Intercept) -2.918276 9.584943

# missing values
x <- c(1, 3, NA, 6)
ciMean(x, na.rm = TRUE)
#>        2.5%    97.5%
#> x -2.918276 9.584943