The phrase "about four participants" is correct and usable in written English.
It can be used when estimating or approximating the number of participants in a study, event, or activity.
Example: "The survey was conducted with about four participants, which provided limited insights into the topic."
Alternatives: "approximately four participants" or "roughly four participants".
In December, 2011, a rally organized by Solidarity unexpectedly drew about ten thousand participants.
Their first one had about ten thousand participants, who were already calling themselves the "nerdfighters".
Wakeboarding has about three million participants in the United States, said Matt Hickman, the editor of WakeBoarding magazine in Winter Park, Fla.
About twenty participants gathered around a long table at the front of the restaurant and introduced themselves.
They also organize an annual march to commemorate the killing; this past weekend, it drew about eight thousand participants — the lowest number yet.
We report data gathered from about thirty thousand participants of a massive web poll of people's cognitive skills, which included ToM and executive functions.
This year, it's shorter by a week, and more focussed, with about seventy participants divided into three general categories seasoned ensembles, new choreographers, and an intimate studio series with different rosters each night.
In a commentary with "Spellbound," Jeff Blitz's documentary about eight participants in the 1999 National Spelling Bee, the producer Sean Welch says that Mr. Blitz has a stutter that is made worse by microphones.
The Sunday before the winter solstice, Christine Cleere, the lead priest of a Druid group called the Gorsedd of Cor Gawr, led about eighty participants in a twilight ritual inside the stone circle.
This year, it's shorter by a week, and more focussed, with about seventy participants divided into three general categories — seasoned ensembles, new choreographers, and an intimate studio series — with different rosters each night.
