You are planning a study testing the efficacy of a new drug to decrease LDL cholesterol. There will be a placebo and experimental group. You expect to be able to find a mean difference in LDL cholesterol of 5 units (using a 95% confidence interval). The common standard deviation is assumed to be 15. You will use a two-sided test at a 5% level of significance, and you want 80% power to detect this difference. You expect a 10% attrition over the length of the study. What is the total sample size that you will need for this study (remember, there are 2 groups).