The phrase "a group of approximately" is correct and usable in written English.
It can be used when you want to indicate an estimated number of people or things in a group.
Example: "The study surveyed a group of approximately 50 participants to gather data on their preferences."
Alternatives: "a cluster of about" or "a collection of roughly".
"Public services describe a group of approximately 500,000 'forgotten families' who bump along the bottom of society".
Our next project phase will be to pilot this intervention with a group of approximately 50 farmers.
During one meeting cited by the Obama campaign, on November 10 , 1993 Mrs. Clinton spoke to a group of approximately 120 participants at a Nafta briefing.
Border Patrol Agents (BPA) assigned to El Paso Sector, El Paso Station (EPT/EPS) apprehended a group of approximately 127 illegal aliens.
This year, the number of teams effectively doubled, and a group of approximately 50 high school students from China competed as well.
The Stanford Symphonic Chorus is a group of approximately 180 students, faculty, staff, and members of the community led by Director of Music and Conductor Stephen Sano.
Alkaloids are a group of approximately 12 000 low molecular weight and nitrogenous secondary metabolites found in 20% of plant species.
"On Tuesday evening a group of approximately 20 students occupied the Vera Anstey Room in the Old Building at LSE, highlighting a broad range of demands relating to higher education," it read.
For Johnny Salvatore, a member of the Brooklyn Brigade, a group of approximately twenty Nets fans who attend games together every three weeks or so, it was an emotional moment.
Raising more than €2,000 for an orphanage, the run was completed by a group of approximately 50 tourists, organised by Koryo Tours.
In contrast, we see the whole range of animal social systems within a group of approximately 40 species of closely related shrimp, a situation unique among all animals.
