Chwirut2               package:NISTnls               R Documentation

_U_l_t_r_a_s_o_n_i_c _c_a_l_i_b_r_a_t_i_o_n _d_a_t_a _2

_D_e_s_c_r_i_p_t_i_o_n:

     The `Chwirut2' data frame has nr rows and nc columns giving

_A_r_g_u_m_e_n_t_s:

       y: A numeric vector of ultrasonic response values. 

       x: A numeric vector of metal distance values. 

_F_o_r_m_a_t:

     This data frame contains the following columns:

_D_e_t_a_i_l_s:

     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.

_S_o_u_r_c_e:

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

_E_x_a_m_p_l_e_s:

     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" )

