For a specific region of interest, the probability, pi, of mutation in tumor i is a function of the length of that region and the expected mutation rates of individual nucleotides in that region under the null hypothesis. Assuming qi, j is the mutation probability of nucleotide j in tumor i, and l is the length of the region of interest:\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p_i = 1 - \mathop {\prod }\limits_{j = 0}^l (1 - q_{i,j})$$\end{document}pi=1-∏j=0l(1-qi,j)