Chwirut2 {NISTnls}R Documentation

Ultrasonic calibration data 2

Description

The Chwirut2 data frame has nr rows and nc columns giving

Arguments

y A numeric vector of ultrasonic response values.
x A numeric vector of metal distance values.

Format

This data frame contains the following columns:

Details

These data are the result of a NIST study involving ultrasonic calibration. The response variable is ultrasonic response, and the predictor variable is metal distance.

Source

Chwirut, D., NIST (197?). Ultrasonic Reference Block Study.

Examples

library(NISTnls)
data(Chwirut2)
plot(y ~ x, data = Chwirut2)
fm1 <- nls(y ~ exp(-b1*x)/(b2+b3*x), data = Chwirut2, trace = TRUE,
           start = c(b1 = 0.1 , b2 = 0.01, b3 = 0.02) )
fm2 <- nls(y ~ exp(-b1*x)/(b2+b3*x), data = Chwirut2, trace = TRUE,
           start = c(b1 = 0.15 , b2 = 0.008, b3 = 0.01) )
fm3 <- nls(y ~ exp(-b1*x)/(1+p3*x), data = Chwirut2, trace = TRUE,
           start = c(b1 = 0.1, p3 = 2.), alg = "plinear" )
fm4 <- nls(y ~ exp(-b1*x)/(1+p3*x), data = Chwirut2, trace = TRUE,
           start = c(b1 = 0.15, p3 = 0.01/0.008), alg = "plinear" )

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