All the virus-testing to date has been of people who are already sick. This was a "representative sample" of 3,000 New Yorkers to show who had antibodies — and therefore had been sick, at least as of two weeks ago — whether they had symptoms or not. Governor Cuomo cautioned that the results are very preliminary, and future surveys need to gather much more data. Still, he said it could eventually help guide which regions of the state start to open, and when. Epidemiologists were skeptical of the value of the survey. They say the sample is minuscule and not at all representative, because it only captured people who were out and about, going to grocery stores and other retailers where researchers gathered their blood via finger-prick. They also faulted the state Health Department for refusing to release survey protocols and to include margins of error — what statisticians call the confidence intervals — with the results.