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P_{x}=\operatorname{pr}\left(\mathrm{LSL}_{x} \leq x \leq \mathrm{USL}_{x}\right)=\Phi\left(\frac{\mathrm{USL}_{x}-\mu_{x}}{\sigma_{x}}\right)-\Phi\left(\frac{\mathrm{LSL}_{x}-\mu_{x}}{\sigma_{x}}\right)