

warpbreaks {base}                            R Documentation

_T_h_e _N_u_m_b_e_r _o_f _B_r_e_a_k_s _i_n _Y_a_r_n _d_u_r_i_n_g _W_e_a_v_i_n_g

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

     This data set gives the number of warp breaks per loom,
     where a loom corresponds to a fixed length of yarn.

_U_s_a_g_e_:

     data(warpbreaks)

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

     A data frame with 54 observations on 3 variables.

      [,1]      breaks       numeric      The number of breaks
      [,2]      wool         factor       The type of wool (A or B)
      [,3]      tension      factor       The level of tension (L, M, H)

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

     L. H. C. Tippet (1950).  Technological Applications of
     Statistics, Wiley, page 106.

_R_e_f_e_r_e_n_c_e_s_:

     Tukey, J. W. (1977).  Exploratory Data Analysis.  Addi-
     son-Wesley.  McNeil, D. (1977).  Interactive Data Anal-
     ysis.  Wiley.

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

     data(warpbreaks)
     summary(warpbreaks)
     opar <- par(mfrow = c(1,2), oma = c(0, 0, 1.1, 0))
     plot(breaks ~ tension, data = warpbreaks, col = "lightgray",
          varwidth = TRUE, subset = wool == "A", main = "Wool A")
     plot(breaks ~ tension, data = warpbreaks, col = "lightgray",
          varwidth = TRUE, subset = wool == "B", main = "Wool B")
     mtext("warpbreaks data", side = 3, outer = TRUE)
     par(opar)
     summary(fm1 <- lm(breaks ~ wool*tension, data = warpbreaks))
     anova(fm1)

