Compute standard errors (between-subjects)

Source: R/se.R

se is used to compute the standard error(s) for one or more variables, for one or more groups in a dataframe.

stderror(data = NULL, measurevar, groupvars = NULL,
na.rm = TRUE, conf.interval = 0.95, tonumeric = TRUE)

Arguments

data

a dataframe
measurevar

the name(s) of column(s) that contain the variable to be summariezed
groupvars

a vector containing names of columns that contain grouping variables
na.rm

boolean that indicates whether to ignore NA values
conf.interval

confidence interval range
tonumeric

whether to convert variables/columns to numeric whenever possible

Value

A data.table

Note

Code adapted from R cookbook (see references)

Author

Hause Lin

Examples

stderror(data = mtcars, measurevar = c("mpg", "disp"), groupvars = c("cyl", "am"))

#> $mpg
#>    cyl am  N      mpg        sd        se       ci
#> 1:   4  0  3 22.90000 1.4525839 0.8386497 3.608418
#> 2:   4  1  8 28.07500 4.4838599 1.5852839 3.748601
#> 3:   6  0  4 19.12500 1.6317169 0.8158584 2.596426
#> 4:   6  1  3 20.56667 0.7505553 0.4333333 1.864483
#> 5:   8  0 12 15.05000 2.7743959 0.8008991 1.762767
#> 6:   8  1  2 15.40000 0.5656854 0.4000000 5.082482
#> 
#> $disp
#>    cyl am  N     disp        sd        se        ci
#> 1:   4  0  3 135.8667 13.969371  8.065220  34.70184
#> 2:   4  1  8  93.6125 20.476777  7.239634  17.11901
#> 3:   6  0  4 204.5500 44.742634 22.371317  71.19552
#> 4:   6  1  3 155.0000  8.660254  5.000000  21.51326
#> 5:   8  0 12 357.6167 71.823494 20.733657  45.63447
#> 6:   8  1  2 326.0000 35.355339 25.000000 317.65512
#> 
stderror(data = ChickWeight, measurevar = "weight", groupvars = "Diet")

#>    Diet   N   weight       sd       se        ci
#> 1:    1 220 102.6455 56.65655 3.819784  7.528242
#> 2:    2 120 122.6167 71.60749 6.536840 12.943596
#> 3:    3 120 142.9500 86.54176 7.900146 15.643078
#> 4:    4 118 135.2627 68.82871 6.336197 12.548506