There is a new intervention method proposed to reduce the Covid infections during the pandemic. Assume we want to calculate the sample size to reduce the infection rate by 10% by comparing to the control group? How large the sample size is needed to detect a 10% difference with a type I error rate of 0.05 (two sided) with a power of 80%? Assume a 20% dropout rate is considered, how large the sample size is needed? Show R code.