T-Test: One-Sample (on)

The on implementation performs a one-sample t-test for one or more variables via on(). Each variable is tested independently against a hypothesized mean.

Arguments

The following arguments are passed via ... in TTEST() or via():

.mu

Numeric. Hypothesized mean under H\(_0\). Default 0.

.alt

Direction: "two.sided", "greater", or "less". Default "two.sided".

.ci

Confidence level. Default 0.95.

.true_mu

Only meaningful via state_null(). Carries the scalar as written in the claim, purely for display in true_mu. Default NULL, falling back to .mu. Not intended to be set directly.

Variants

"multi"

Tests multiple variables supplied via on(). Accepts the same .mu, .alt, .ci arguments as the default. .mu is recycled across all variables or must match their count.

One-sample t-test default class

By default, returns a class_ttest_one object. All variants that also return class_ttest_one inherit auto_tidy() and print() automatically. Otherwise, to process outputs:

• print(): Write it down through print from variant().

• tidy(): Use making_tidy() to register a tidy method if needed.

Hypothesis claims

Supports MU() via state_null():

define_model(on(x), <data>) |>
    prepare_test(TTEST) |>
    state_null(MU(x) >= 1) |>
    conclude()

Scaled claims are supported: 2 * MU(extra) == 4 tests MU(extra) == 2. true_mu in the output shows the right-hand scalar as written (4), while the test runs on the solved value (2).

See also

Other ttest-implementations: ttest-formula, ttest-pairwise, ttest-xby

Examples

# single variable
sleep |>
    define_model(on(extra)) |>
    prepare_test(TTEST) |>
    conclude()
#> 
#> == Model ======================================================================= 
#> 
#> Variable Mapper : on 
#> Args : extra 
#> 
#> == T-Test ====================================================================== 
#> 
#> -- Summary ---------------------------------------------------------------------
#> 
#> ────────────────────────────────────────────
#>   term   estimate  true_mu  t_stat  p_val   
#> ────────────────────────────────────────────
#>   extra   1.540       0     3.413   <0.001  
#> ────────────────────────────────────────────
#> 
#> 
#> -- Confidence Interval ---------------------------------------------------------
#> 
#> ─────────────────────────────
#>   term   lower_95  upper_95  
#> ─────────────────────────────
#>   extra   0.596     2.484    
#> ─────────────────────────────
#> 
#> 

# null hypothesis expression
sleep |>
    define_model(on(extra)) |>
    prepare_test(TTEST) |>
    state_null(MU(extra) >= 1) |>
    conclude()
#> 
#> == Model ======================================================================= 
#> 
#> Variable Mapper : on 
#> Args : extra 
#> 
#> == T-Test ====================================================================== 
#> 
#> -- Summary ---------------------------------------------------------------------
#> 
#> ───────────────────────────────────────────
#>   term   estimate  true_mu  t_stat  p_val  
#> ───────────────────────────────────────────
#>   extra   1.540       1     1.197   0.877  
#> ───────────────────────────────────────────
#> 
#> 
#> -- Confidence Interval ---------------------------------------------------------
#> 
#> ─────────────────────────────
#>   term   lower_95  upper_95  
#> ─────────────────────────────
#>   extra    -Inf     2.320    
#> ─────────────────────────────
#> 
#> 

# multiple variables
iris |>
    define_model(on(where(is.numeric))) |>
    prepare_test(TTEST) |>
    via("multi") |>
    conclude()
#> 
#> == Model ======================================================================= 
#> 
#> Variable Mapper : on 
#> Args : where(is.numeric) 
#> 
#> == T-Test · multi ============================================================== 
#> 
#> -- Summary ---------------------------------------------------------------------
#> 
#> ───────────────────────────────────────────────────
#>       term      estimate  true_mu  t_stat  p_val   
#> ───────────────────────────────────────────────────
#>   Sepal.Length   5.843       0     86.425  <0.001  
#>   Sepal.Width    3.057       0     85.908  <0.001  
#>   Petal.Length   3.758       0     26.073  <0.001  
#>   Petal.Width    1.199       0     19.271  <0.001  
#> ───────────────────────────────────────────────────
#> 
#> 
#> -- Confidence Interval ---------------------------------------------------------
#> 
#> ────────────────────────────────────
#>       term      lower_95  upper_95  
#> ────────────────────────────────────
#>   Sepal.Length   5.710     5.977    
#>   Sepal.Width    2.987     3.128    
#>   Petal.Length   3.473     4.043    
#>   Petal.Width    1.076     1.322    
#> ────────────────────────────────────
#> 
#>