according to the oxnard college student success committee report in the previous year, we believe that 20% of students struggle in their classes because they don't spend more than 8 hours studying independently outside of a 4-unit class. for this year, you would like to obtain a new sample to estimate the proportiton of all oxnard students who struggle in their classes because they don't study enough outside of the classrooms. you would like to be 99% confident that your estimate is within 3.5% of the true population proportion. how large of a sample size is required? do not round mid-calculation.