5Question: A virologist is analyzing 7 viral strains, of which 4 are enveloped viruses and 3 are non-enveloped. If she selects 3 strains at random for further testing, what is the probability that exactly 2 are enveloped viruses?

Sun, 03 May 2026 18:19:36 +0000

**Would Testing Patterns in Viral Strains Influence Public Health Decisions?**
Curious scientists and medical professionals are increasingly exploring how viral structure affects testing accuracy and outbreak response. Right now, a thought-provoking question is gaining attention: A virologist is analyzing 7 viral strains—4 enveloped and 3 non-enveloped—and considering which 3 to test further. The aim is to calculate the precise probability of selecting exactly 2 enveloped strains. This calculation isn’t just academic—it reflects real-world challenges in tracking infectious diseases and designing effective diagnostics. ### Why This Question Matters in US Science and Health Conversations
With rising interest in viral behavior, genomic epidemiology, and lab testing efficiency, understanding transmission dynamics through probability models helps inform public health strategies. As viral strains influence how quickly diseases spread and which tests detect infections, modeling these outcomes supports better resource planning and research investment. This probabilistic lens offers clarity amid complex biological variables. ### A Clear, Neutral Explanation of the Probability Calculation The scenario involves selecting 3 strains from 7 total—4 enveloped, 3 non-enveloped—without replacement. To find the chance of exactly 2 enveloped viruses, we calculate combinations: