qqt                  package:limma                  R Documentation

_S_t_u_d_e_n_t'_s _t _Q_u_a_n_t_i_l_e-_Q_u_a_n_t_i_l_e _P_l_o_t

_D_e_s_c_r_i_p_t_i_o_n:

     Plots the quantiles of a data sample against the theoretical
     quantiles of a Student's t distribution.

_U_s_a_g_e:

     qqt(y, df = Inf, ylim = range(y), main = "Student's t Q-Q Plot", 
         xlab = "Theoretical Quantiles", ylab = "Sample Quantiles", plot.it = TRUE, ...) 

_A_r_g_u_m_e_n_t_s:

       y: a numeric vector or array containing the data sample

      df: degrees of freedom for the t-distribution.  The default
          'df=Inf' represents the normal distribution.

    ylim: plotting range for 'y'

    main: main title for the plot

    xlab: x-axis title for the plot

    ylab: y-axis title for the plot

 plot.it: whether or not to produce a plot

     ...: other arguments to be passed to 'plot'

_D_e_t_a_i_l_s:

     This function is analogous to 'qqnorm' for normal probability
     plots. In fact 'qqt(y,df=Inf)' is identical to 'qqnorm(y)' in all
     respects except the default title on the plot.

_V_a_l_u_e:

     A list is invisibly returned containing the values plotted in the
     QQ-plot: 

       x: theoretical quantiles of the t-distribution

       y: the data sample, same as input 'y'

_A_u_t_h_o_r(_s):

     Gordon Smyth

_S_e_e _A_l_s_o:

     'qqnorm'

_E_x_a_m_p_l_e_s:

     #  See also the lmFit examples

     y <- rt(50,df=4)
     qqt(y,df=4)
     abline(0,1)

