coef_diff_by_group {breathtestcore} R Documentation

## Tabulates breath test parameter differences of groups

### Description

Given a fit to 13C breath test curves, computes between-group confidence intervals and p-values, for examples of the half emptying time `t50`, with correction for multiple testing.

### Usage

```coef_diff_by_group(fit, mcp_group = "Tukey", reference_group = NULL, ...)
```

### Arguments

 `fit` Object of class `breathtestfit`, for example from `nlme_fit`, `nls_fit` `mcp_group` "Tukey" (default) for all pairwise comparisons, "Dunnett" for comparisons relative to the reference group. `reference_group` Used as the first group and as reference group for `mcp_group == "Dunnett"` `...` Not used

### Value

A `tibble` of class `coef_diff_by_group` with columns

parameter

Parameter of fit, e.g. `beta, k, m, t50`

method

Method used to compute parameter. `exp_beta` refers to primary fit parameters `beta, k, m`. `maes_ghoos` uses the method from Maes B D, Ghoos Y F, Rutgeerts P J, Hiele M I, Geypens B and Vantrappen G 1994 Dig. Dis. Sci. 39 S104-6. `bluck_coward` is the self-correcting method from Bluck L J C and Coward W A 2006

groups

Which pairwise difference, e.g `solid - liquid`

estimate

Estimate of the difference

conf.low, conf.high

Lower and upper 95 A comparison is significantly different from zero when both estimates have the same sign.

p.value

p-value of the difference against 0, corrected for multiple testing

### Examples

```library(dplyr)
data("usz_13c")
data = usz_13c %>%
dplyr::filter( patient_id %in%
c("norm_001", "norm_002", "norm_003", "norm_004", "pat_001", "pat_002","pat_003")) %>%
cleanup_data()
fit = nls_fit(data)
coef_diff_by_group(fit)

fit = nlme_fit(data)
coef_diff_by_group(fit)

# TODO: Add example for Stan fit typecast to class \code{breathtestfit} to compute
# confidence intervals instead of credible intervals
```

[Package breathtestcore version 0.8.1 Index]