An infectious disease specialist is studying the effect of a new antibiotic on a bacterial infection. The number of bacteria in the culture on day 1 is estimated at 400000. A dose of antibiotic is applied to the culture. At the end of 1 week, the number of bacteria in the culture is estimated at 6250. The study is discontinued at the end of 2 weeks and the antibiotic is deemed effective because the estimated number of bacteria was just under 50.