C$-$Spec, Inc., is attempting to determine whether an existing machine is capable of milling and engine part that has a key specification of $4+-0\mathrm{.}003$ inches. After a trial run on this machine, C$-$Spec has determined that the machine has a sample mean of $4\mathrm{.}001$ inches with a standard deviation of $\mathrm{.}002$ inch. The $C_{pk}$ for this machine is