The phrase "a quartile" is correct and usable in written English.
It is typically used in statistics to refer to one of the four equal parts into which a data set can be divided.
Example: "The first quartile represents the 25th percentile of the data set, indicating that 25% of the values fall below this point."
Alternatives: "one-fourth segment" or "25th percentile".
Interestingly, the Yankees, who are in a quartile all their own, wouldn't be in these playoffs if not for some of their least expensive players.
Stratification of percent inhibition P2Y12 isolated a quartile of clopidogrel nonresponders (inhibition P2Y12 <15%) with significantly higher incidence of PMI (44% vs 15%, odds ratio 4.6, 95% confidence interval 1.9 to 11.5, p = 0.001).
Each vertical line represents the boundary of a quartile.
In the case of family income, we used two approaches to detecting non-linearity: a semilog model in which ECEC use was regressed on the log of income and a quartile model in which ECEC use was regressed on three dummy variables indicating family income quartiles (with the wealthiest quartile excluded as the comparison group).
A quartile slower walking speed was associated with a mortality hazard ratio (HR) of 1.38 [4].
A quartile change in walking speed is approximately one SD change (in terms of normal distributions).
The presences of type 2 diabetes across fetuin-A quartile groups were 27.3%, 26.6%, 33.6%, and 34.8%, respectively.
The presence of type 2 diabetes in the highest fetuin-A quartile was higher than that in the lowest quartile (p<0.0001).
Compared with participants in the lowest fetuin-A quartile, those with higher concentrations were more likely to be female and Caucasian, to have type 2 diabetes, and to have had higher BMI, waist circumference, HOMA-IR, C-reactive protein, triglycerides, and LDL cholesterol (Table 1).
Age was categorized as a quartile-categorical variable.
When distribution is skewed, a quartile-based method is an option [ 11].
