Equating of multiple forms using Item Response Theory (IRT) methods. See Battauz (2025) <doi:10.18637/jss.v115.i11> for a detailed description of the package. See Battauz M. (2017) <doi:10.1007/s11336-016-9517-x>, Battauz and 'Leoncio' (2023) <doi:10.1177/01466216231151702> and Haberman S. J. (2009) <doi:10.1002/j.2333-8504.2009.tb02197.x>) for the methods to link multiple test forms.

The goal of 'equatiomatic' is to reduce the pain
    associated with writing 'LaTeX' formulas from fitted models. The
    primary function of the package, extract_eq(), takes a fitted model
    object as its input and returns the corresponding 'LaTeX' code for the
    model.

In agricultural, post-harvest and processing, engineering and industrial experiments factors are often differentiated with ease with which they can change from experimental run to experimental run. This is due to the fact that one or more factors may be expensive or time consuming to change i.e. hard-to-change factors. These factors restrict the use of complete randomization as it may make the experiment expensive and time consuming. Split plot designs can be used for such situations. In general model estimation of split plot designs require the use of generalized least squares (GLS). However for some split-plot designs ordinary least squares (OLS) estimates are equivalent to generalized least squares (GLS) estimates. These types of designs are known in literature as equivalent-estimation split-plot design. For method details see, Macharia, H. and Goos, P.(2010) <doi:10.1080/00224065.2010.11917833>.Balanced split plot designs are designs which have an equal number of subplots within every whole plot. This package used to construct equivalent estimation balanced split plot designs for different experimental set ups along with different statistical criteria to measure the performance of these designs. It consist of the function equivalent_BSPD().

Saturation of ionic substances in urine is calculated based on
  sodium, potassium, calcium, magnesium, ammonia, chloride, phosphate, sulfate,
  oxalate, citrate, ph, and urate.  This program is intended for research use,
  only.  The code within is translated from EQUIL2 Visual Basic code based on
  Werness, et al (1985) "EQUIL2: a BASIC computer program for the calculation
  of urinary saturation" <doi:10.1016/s0022-5347(17)47703-2> to R. The Visual
  Basic code was kindly provided by Dr. John Lieske of the Mayo Clinic.