Chwirut2 {NISTnls}

Ultrasonic calibration data 2

Description

The Chwirut2 data frame has nr rows and nc columns giving

Format

This data frame contains the following columns:

y

A numeric vector of ultrasonic response values.

x

A numeric vector of metal distance values.

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

Try <- function(expr) if (!inherits(val <- try(expr), "try-error")) val
plot(y ~ x, data = Chwirut2)
Try(fm1 <- nls(y ~ exp(-b1*x)/(b2+b3*x), data = Chwirut2, trace = TRUE,
            start = c(b1 = 0.1 , b2 = 0.01, b3 = 0.02)))
Try(fm1a <- nls(y ~ exp(-b1*x)/(b2+b3*x), data = Chwirut2, trace = TRUE,
             start = c(b1 = 0.1 , b2 = 0.01, b3 = 0.02), alg = "port"))
Try(fm2 <- nls(y ~ exp(-b1*x)/(b2+b3*x), data = Chwirut2, trace = TRUE,
            start = c(b1 = 0.15 , b2 = 0.008, b3 = 0.01)))
Try(fm2a <- nls(y ~ exp(-b1*x)/(b2+b3*x), data = Chwirut2, trace = TRUE,
             start = c(b1 = 0.15 , b2 = 0.008, b3 = 0.01), alg = "port"))
Try(fm3 <- nls(y ~ exp(-b1*x)/(1+p3*x), data = Chwirut2, trace = TRUE,
           start = c(b1 = 0.1, p3 = 2.), alg = "plinear"))
Try(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"))