| Fleishman.coef.NN {BinOrdNonNor} | R Documentation |
Computes the Fleishman coefficients for each continuous variable
Description
The function checks whether the skewness and kurtosis parameters violates the universal equality given in Demirtas, Hedeker, Mermelstein (2012) and computes the Fleishman coefficients for each continuous variable with pre-specified skewness and kurtosis values by solving the Fleishman's polynomial equations using BBsolve function in BB package.
Usage
Fleishman.coef.NN(skew.vec, kurto.vec)
Arguments
skew.vec |
The skewness vector for continuous variables. |
kurto.vec |
The kurtosis vector for continuous variables. |
Value
An matrix with four columns corresponding to the four Fleishman coefficients, and number of rows corresponding to number of continuous variables. The i-th row contains the estimates of the four Fleishman coefficients a, b, c and d for the i-th continuous variable with i-th pre-specified skewness and kurtosis values.
References
Demirtas, H., Hedeker, D., and Mermelstein, R.J. (2012). Simulation of massive public health data by power polynomials. Statistics in Medicine, 31(27), 3337-3346.
Fleishman, A.I. (1978). A method for simulating non-normal distributions. Psychometrika, 43(4), 521-532.
Examples
# Consider four continuous variables, which come from
# Exp(1),Beta(4,4),Beta(4,2) and Gamma(10,10), respectively.
# Skewness and kurtosis values of these variables are as follows:
skew.vec <- c(2,0,-0.4677,0.6325)
kurto.vec <- c(6,-0.5455,-0.3750,0.6)
coef.est <- Fleishman.coef.NN(skew.vec, kurto.vec)