View source: R/GRS.Powerfunc.R
GRS.Powerfunc | R Documentation |
The function plots the power functions for a range of sample size (T), given the other parameter values
GRS.Powerfunc(Tvec, N, K, theta, alpha = 0.05)
Tvec |
a vector of sample sizes |
N |
the number of portfolio returns |
K |
the number of risk factors |
theta |
maximum Sharpe ratio of the K factor portfolios |
alpha |
the level of significance, default is 0.05 |
The power is plotted against the ratio=theta/thetas, the proprotion of potential efficiency
Power: Matrix of power values plotted
Under H0: ratio = 1, so the power = alpha when ratio = 1.
The power increases as the ratio declines from 1.
The power increases with sample size, so the upper power function is associated with larger sample size.
Jae H. Kim
Gibbons, Ross, Shanken, 1989. A test of the efficiency of a given portfolio, Econometrica, 57,1121-1152. <DOI:10.2307/1913625>
GRS (1989) <DOI:10.2307/1913625>
GRS.Powerfunc(Tvec=c(60,120),N=25, K=3,theta=0.3) # Figure 2 of Kim and Shamsuddin (2016)
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