ntp: ntp data

In nlr: Nonlinear Regression Modelling using Robust Methods

Description

Cromium concentration in blood and kidney of Mouse, Rat, and Guinea pig.

Usage

data(ntp)

Format

The format is:data.frame chr "ntp"

• dm.k, cm.k, Dose (x) and Chromium Concentration (y) in Mouse kidney.

• dr.b, cr.b, Dose (x) and Chromium Concentration (y) Rat blood.

• dr.k, cr.k, Dose (x) and Chromium Concentration (y) Rat kidney.

• dp.b, cp.b, Dose (x) and Chromium Concentration (y) Guinea pig blood.

• dp.k, cp.k, Dose (x) and Chromium Concentration (y) in Guinea pig kidney.

Details

Lim et al. (2010) illustrated the Weighted M-Estimate (WME) methodology with real data from National Toxicology study Program (NTP 2007. pp. 11-12). NTP (2007) conducted 3-month and 2-year studies, where rodents were exposed to CrVI administered in drinking water as sodium dichromate dihydrate.The dose concentrations were 0, 2.87, 8.62, 28.7, 86.2, 287, and 862mg sodium dichromate dihyrate/L (to yield 0, 1, 3, 10, 30, 100, and 300 mg chromium/L). When animals were sacrificed, total chromium concentrations in blood, kidneys, and femurs were measured. Lim et al. (2010) proposed the hill model for the data

θ_0 + \frac{θ_1 x_i^{θ_2}}{θ_3^{θ_2}+x_i^{θ_2}}

with heterogeneous standard deviation

τ_0+\frac{τ_1}{1+e^{-τ_2 x_i}}

Source

National Toxicology Program, 2007. NTP Toxicity Studies of Sodium Dichromate Dihydrate (CAS No. 7789-12-0) Administered in Drinking Water to Male and Female F344/N Rats and B6C3F1 Mice and Male BALB/c and am3-C57BL/6 Mice. Toxicity Report Series 72, 1-G4, U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health, RTP, North Carolina, U.S.A.

References

Lim, C., Sen, P. K., Peddada, S. D. (2010). Statistical inference in nonlinear regression under heteroscedasticity. Sankhya B 72:202-218.

Examples

data(ntp)
## maybe strnt ntp

nlr documentation built on July 31, 2019, 5:09 p.m.