The phrase "a marked association" is correct and usable in written English.
It can be used to describe a significant or noticeable relationship between two or more variables or factors in various contexts, such as research or analysis.
Example: "The study revealed a marked association between high levels of stress and decreased productivity among employees."
Alternatives: "a significant correlation" or "a strong link".
This far exceeds our threshold of significance of 5 for LOD scores [17] and suggests a marked association of local ancestry at this locus with Lp(a) level.
We observed a marked association between the occurrence of DFWC and the duration of nCPAP treatment, this again lending support to earlier findings [9], [10], [11], [12], [13], [14], [15].
The Asp541Glu genotype had a marked association with familial prostate cancer risk.
However, the combination of these genotypes showed a marked association with breast carcinoma risk.
A marked association was also observed in our patients between postoperative haemorrhage and need for intensive care.
We found a marked association of Prevotella copri with new-onset RA (NORA) patients and not with other patient groups.
Separate analyses suggested that associations between IQ and attempted suicide were restricted to men without psychosis; in men with psychosis we found no evidence of any marked association between IQ and attempted suicide.
Although the role of the population density was less obvious, a more marked association was found above a certain threshold.
The estimated β-coefficients for miR-30e* suggested a significant protective effect for the high expression levels and a more marked association with outcome in the former case.
A more marked association was found for residual core mood symptoms.
This study was started prior to our 2004 publication reporting a more marked association between dietary Si intake and bone mineral density in pre-menopausal women compared to men and post-menopausal women, suggesting a Si estrogen interaction [18].
