The phrase "a sample of roughly" is correct and usable in written English.
It can be used when you want to indicate an approximate quantity or measurement of a sample in a specific context, such as research or analysis.
Example: "We collected a sample of roughly 100 participants for the study to ensure diverse representation."
Alternatives: "an approximate sample of" or "a sample of about".
The other paper uses a sample of roughly 8,000 firm-years of data from U.S. family firms (from 1993 to 2009).
The researchers analyzed a sample of roughly 200 commenters -- annalyzing publicly available information on their profiles to determine their social networks.
Nielsen measures the television viewership of a sample of roughly 25,000 households across the United States, and it works hard to ensure that the sample is not coerced to watch specific shows or channels.
Harvard Business Review tested this idea and created a sample of roughly 2,140 top executives in S&P 1500 firms.
This produced a sample of roughly 60 70% of all non-cardiac operations in the VASQIP database for those years (n=507 545).
The National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), sponsored by NIAAA, collected data on alcohol and other drug use from a sample of roughly 46,500 citizens 18 and older using face-to-face computer-assisted interviews.
One analysis of a sample of the roughly $55 billion in outstanding tobacco bonds foresees the potential for a handful of full-blown defaults more than a decade from now, but the continuing legal dispute could mean deeper problems sooner.
A single, black raven doesn't do much to support the hypothesis that 50% of ravens are black, but a large sample of roughly half black, half white ravens would.
Exemplifying the inhumanity of U.S. immigration and border enforcement policies, the mass prosecution program called Operation Streamline, begun in Del Rio, TX in 2005 and brought to Tucson in Jan . 2008 daily takes a large sample of roughly 70 newly captured migrants and gives them criminal records and often lengthy jail sentences.
For the qualitative component of the study, a convenience sample of roughly 40 physicians was achieved in the following manner.
Sino-MONICA, conducted from 1985 1993 in 17 monitoring units in 16 provinces of China, was a surveillance sample of roughly 5,000,000 people, and Sino-MONICA surveillance has continued from 1994 to the present in a sub-population of approximately 170,000 people in Beijing.
