Confidence interval for difference of the mean between 2 samples (unknown sigmas)

Source: R/ci_t2.R

Calculates the confidence interval for the difference of the mean between 2 samples (t distribution).

ci_t2(x1, s1, n1, x2, s2, n2, var.equal = FALSE, conf.level = 0.95, digits = 2)

Arguments

x1

Sample's 1 mean
s1

Sample's 1 standard deviation
n1

Sample size of sample 1
x2

Sample's 2 mean
s2

Sample's 2 standard deviation
n2

Sample size of sample 2
var.equal

Logical indicating if the variances are equal or not
conf.level

Confidence level to use for the confidence interval (Default is 0.95)
digits

Number of digits to round to (Default is 2)

Value

A tibble with the difference of means, degrees of freedom, and lower and upper ends of the confidence interval

Examples

x1 <- 90
s1 <- 15
n1 <- 20
x2 <- 80
s2 <- 8
n2 <- 30
ci_t2(x1, s1, n1, x2, s2, n2)

#> # A tibble: 1 × 4
#>   mean_diff    df lower upper
#>       <dbl> <dbl> <dbl> <dbl>
#> 1        10  26.3  2.48  17.5