Name:

Description:

This is a data set consisting of measurements of water salinity (i.e., its salt concentration) and river discharge taken in North Carolina's Pamlico Sound, recording some bi-weekly averages in March, April, and May from 1972 to 1977. This dataset was listed by Ruppert and Carroll (1980). In Carrol and Ruppert (1985) the physical background of the data is described. They indicated that observations 5 and 16 correspond to periods of very heavy discharge and showed that the discrepant observation 5 was masked by observations 3 and 16, i.e., only after deletion of these observations it was possible to identify the influential observation 5.

This data set is a prime example of the masking effect.

Variables:

A data frame with 28 observations on the following 5 variables (in parentheses are the names used in the 1980 reference).

X1:

Lagged Salinity (‘SALLAG’)

X2:

Trend (‘TREND’)

X3:

Discharge (‘H2OFLOW’)

Y:

Salinity (‘SALINITY’)

Link To Google Sheets:

Rows:

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References/Notes/Attributions:

Source

P. J. Rousseeuw and A. M. Leroy (1987) Robust Regression and Outlier Detection; Wiley, p.82, table 5.

Ruppert, D. and Carroll, R.J. (1980) Trimmed least squares estimation in the linear model. JASA 75, 828–838; table 3, p.835.

Carroll, R.J. and Ruppert, D. (1985) Transformations in regression: A robust analysis. Technometrics 27, 1–12

R Dataset Upload:

Use the following R code to directly access this dataset in R.

R Coding Interface: