We took 1,300 randomly selected undergraduates, we had them nominate their friends, and we followed both the random students and their friends daily in time to see whether or not they had the flu epidemic.
Kami memilih secara acak 1.300 mahasiswa, kami minta mereka menominasikan teman mereka, kami ikuti mahasiswa yang kami pilih itu dan teman mereka setiap hari untuk melihat apakah mereka terkena epidemi flu.