According to the American Dental Association, there are about 200,000 registered dentists in the US. I’m not going to bore you with the maths here, but to get a statistically significant sample of 200,000 people, you need about 400.
Acorde a la Asociación Dental de EE.UU., hay alrededor de 200 000 dentistas registrados en EE.UU. No voy a aburrir con matemáticas aquí, pero para conseguir una muestra importante de 200 000 personas, necesitas 400.