This page shows how to reproduce Table 1 and Figure 1 presented in the paper and how to obtain results for other settings.
In the paper, the inhibition levels 100% and 50% are used for illustration. The functions below allows the user to compute power and make Figure 1 in other inhibition levels too.
You need free software R or Splus.
Download the R code hts.R , and inside R, type
> source("hts.R")
Part I. Power Calculation
To produce Table 1, for the constant variance situation, use getPower.inh.cv. For example,
> getPower.inh.cv(inh=c(1,0.5),z=0.5)
Z 100% Inhibition Power 50% Inhibition Power
0.500 1.000 0.999
where the parameter inh=inhibition level, it can be either a scalar or a vector. inh=1 means 100% inhibition, corresponding to our "reference power" in Table 1. inh= 0.5 means 50% inhibition level. The parameter z is the Z-factor. You can specify other inhibition levels, for instance,
> getPower.inh.cv(inh=c(1,0.75,0.5,0.25),z=0.25)
Z 100% InhPower 75% InhPower 50% InhPower 25% InhPower
0.250 1.000 0.999 0.841 0.159
When you don't know Z-factor, you can specify the signal mean, negative control mean and the common standard deviation to get the Z-factor and the power as well. Here is the example,
> getPower.inh.cv(mu1=50,mu2=10,sigma=3.3,inh=c(0.2,0.5,0.8))
Z 20% Inhibition Power 50% Inhibition Power 80% Inhibition Power
0.505 0.282 0.999 1.000
where mu1=signal mean, mu2=negative control mean, sigma=SD and inh=inhibition level.
If the constant coefficient of variation (CV) is assumed, then you need use getPower.inh.ccv. To produce Table 1 for the constant CV situation, you do
> getPower.inh.ccv(sb=10,z=0.5,inh=c(1,0.5))
Z CV 100% Inhibition Power 50% Inhibition Power
0.500 0.136 1.000 0.707
> getPower.inh.ccv(sb=5,z=0.5,inh=c(1,0.5))
Z CV 100% Inhibition Power 50% Inhibition Power
0.500 0.111 1.000 0.841
where sb=S/B ratio, z=Z factor and inh is the inhibition level. When you don't know the Z-factor, then you need to specify the signal mean, negative control mean and the constant CV. For example,
> getPower.inh.ccv(mu1=50,mu2=10,tau=0.167,inh=c(1.0,0.5))
Z CV 100% Inhibition Power 50% Inhibition Power
0.249 0.167 1.000 0.157
You can also use S/B to replace mu1 and mu2, like
> getPower.inh.ccv(tau=0.167,sb=5,inh=c(1.0,0.5))
Z CV 100% Inhibition Power 50% Inhibition Power
0.248 0.167 1.000 0.157
where the parameter mu1=signal mean, mu2=negative control mean, tau=CV, sb=S/B ratio and inh is still the inhibition level.
Part II. Figures
Figure 1A: Power v.s. S/B at given CV levels
To reproduce figure 1A, just call the function makefigure1A(inh=0.5), where inh is the inhibition level at 50%. Once you change the inh value, you can get any inhibition level as you want. For instance, use makefigure1A(p=0.4), you will get
Figure 1B: Power v.s. Z-factor at given CV levels
To reproduce figure 1B, just call the function makefigure1B(inh=0.5), where inh is the inhibition level at 50%. If you want to set a different inh value, say 0.4, you can use makefigure1B(inh=0.4), and you will get inhibition level at 40% like
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