a phycologist is interested in determining the proportion of algae samples from a local rivulet that belong to a particular phylum. a simple random sample of 50 alga is obtained and each alga is categorized as either being a cyanobacterium or not. the researcher found that 38 samples were, in fact, cyanobacteria. without relying on any previous knowledge, the researcher wanted to estimate the proportion of algae that were cyanobacteria with a margin of error of at most 0.01 in a 99% confidence interval. how large a sample size would be required?