Before revision:  We assume that n_i/\phi _i' on a given day j is drawn from a Poisson distribution whose mean is robustly estimated from the four neighbouring days, and calculate the inferred Poisson probability P _{ij of the observation.
After revision:  We assume that n_i/\phi '_i on a given day j is drawn from a Poisson distribution whose mean is robustly estimated from the four neighbouring days, and calculate the inferred Poisson probability P _{ij of the observation.