The phrase "a narrow sample" is correct and usable in written English.
It can be used when referring to a limited or restricted selection of data, participants, or observations in research or analysis.
Example: "The study's findings may not be generalizable due to the narrow sample of participants involved."
Alternatives: "a limited sample" or "a small sample".
Most of what we know about the genetic basis of disease risk rests upon a narrow sample of the population.
Yet these represent only a narrow sample of a vast national industry, which at its height was second only to Hollywood in the number of films it produced, some 200 to 500 a year.
Sceptics protest that the study in question relies on a narrow sample of students and a broad definition of sexual assault, including "any unwanted sexual contact" while the victim is incapacitated by alcohol or drugs.In the past, accusations of sexual assault were typically dealt with privately by schools, usually behind closed doors.
Given the breadth and richness of later Mohist thought, this article can present only a narrow sample.
Another potential limitation is the focus on a narrow sample – school employees from one state in the US.
At the same time, that argument reinforces the more central point that self-assessment alone can not be relied upon as a mechanism for judging one's overall skill level as every situation is inevitably a narrow sample of a broader domain that cannot be fully anticipated until the individual is embedded within the experience.
The Customs Service has challenged the findings in the report, saying that the accounting office investigation was based on a narrow sampling of information stored in the computer system.
The way Blum struggled Monday night to explain his vote — through the loud boos of rowdy, impolite and infuriated constituents — is just a narrow sampling of the the growing concern and confusion caused by Republican plans to revamp the nation's health-care system.
The difference between the two models hints a narrow sampling time window as a partially explanation of the large error on the estimated K for the real data.
The analysis was done using a narrower sample of years under review for the period 2008 to 2015.
To carry out this aim, we compared the final model, which included the full study sample, to a narrower sample that excluded individuals who were high cost in the previous year (top 10%% of 2008 expenditures).
