polish this statement: Using OpenEpi persontime method, the results are inconclusivenot supported of a statistically significant improvement and the analysis is hampered by a zero event rate in one group. When comparing between Year 2 and the baseline period, the unexposed group had 0 events resulting a rate ratio of 0, the exposed group had a nonzero rate of 0.391. Because the comparison group has zero events, the rate ratio (RR) is undefined with mathematic calculation with 0 in a denominator. Therefore, all exact tests (z, Fisher, MidP) are nonsignificant. The Taylor/Byar CIs for the RR are very wide and include 1. Formal statistical testing of change from 0.00 to 0.00 (baselineYear 1) and from 0.003.91 (baselineYear 2; Year 1Year 2) is not mathematically calculatable because zero event counts yield a 0 denominator in the Incident rate ratio formula, resulting undefined rate ratios and confidence intervals due to a small population size