Week one assignment was very useful. I learnt alot of things about bias, zero dose and how to calculate weighted averages and sample size. A suvey that is very expensive as delivering vaccination may not be a wise investment. Always think of selection bias when not every house to house and not every one selected is interviewed. I also learn about variables to collect to calculate weighted averages with regards to DPT. We should always think of information bias when percentage of documented evidence is low.