power.casectrl         package:GeneticsBase         R Documentation

_P_o_w_e_r _f_o_r _c_a_s_e-_c_o_n_t_r_o_l _g_e_n_e_t_i_c_s _s_t_u_d_y

_D_e_s_c_r_i_p_t_i_o_n:

     Calculate power for case-control genetics study

_U_s_a_g_e:

     power.casectrl(N, gamma = 4.5, p = 0.15, kp = 0.1, alpha = 0.05, fc = 0.5, 
                     minh = c("multiplicative", "dominant", "recessive"))

_A_r_g_u_m_e_n_t_s:

       N: total number of subjects

   gamma: Relative risk in multiplicative model.  Not used in Dominant 
          or Recessive model.

       p: frequency of A (protective) allele

      kp: significance level

   alpha: prevalence of disease 

      fc: fraction of cases 

    minh: mode of inheritance, one of  

_V_a_l_u_e:

     power for the specified parameter values.

_A_u_t_h_o_r(_s):

     Michael Man

_R_e_f_e_r_e_n_c_e_s:

     Long, A. D. and C. H. Langley (1997). Genetic analysis of  complex
     traits. Science 275: 1328.

_E_x_a_m_p_l_e_s:

     # single calc
     power.casectrl(p=0.1, N=50, gamma=1.1, kp=.1, alpha=5e-2, minh='r')

     # for a range of sample sizes
     power.casectrl(p=0.1, N=c(25,50,100,200,500), gamma=1.1, kp=.1,
                   alpha=5e-2, minh='r')

     # create a power table
     fun <- function(p)
       power.casectrl(p=p, N=seq(100,1000,by=100), gamma=1.1, kp=.1,
                     alpha=5e-2, minh='recessive')

     m <- sapply( X=seq(0.1,0.9, by=0.1), fun )
     colnames(m) <- seq(0.1,0.9, by=0.1)
     rownames(m) <- seq(100,1000,by=100)

     print(round(m,2))

