acid {assist}R Documentation

Lake Acidity Study


The acid data frame has 112 rows and 4 columns of data derived based on the Eastern Lakes Survey of 1984 implemented by the Environmental Protection Agency of the USA.




The data frame contains the following columns:

ph a numeric vector of surface pH values.

t1 a numeric vector of calcium concentrations in log10 milligrams per liter.

x1, x2 numeric vectors of the lakes' geographic locations.


112 lakes are extracted in the southern Blue Ridge mountains area. The surface pH values were recorded together with the calcium concentration and geographic locations.


Douglas, A. and Delampady, M. (1990), Eastern Lake Survey Phase I: Documentation for the Data Base and the Derived Data sets. Tech Report 160 (SIMS), Dept. Statistics, University of British Columbia.


Gu, C. and Wahba, G. (1993) Smoothing Spline ANOVA with component-wise Bayesian confidence intervals. Journal of Computational and Graphic Statistics 55, 353-368.

[Package assist version 3.1.7 Index]