nlr (version 0.1-3)

ntp: ntp data

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 $$ \theta_0 + \frac{\theta_1 x_i^{\theta_2}}{\theta_3^{\theta_2}+x_i^{\theta_2}} $$ with heterogeneous standard deviation $$ \tau_0+\frac{\tau_1}{1+e^{-\tau_2 x_i}} $$

References

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

Examples

# NOT RUN {
data(ntp)
## maybe strnt ntp
# }