The phrase "a variable occurrence of" is correct and usable in written English.
It can be used in contexts where you want to describe something that happens in different instances or situations, often in scientific or technical discussions.
Example: "In the study, we observed a variable occurrence of the phenomenon across different environments."
Alternatives: "a fluctuating instance of" or "an inconsistent manifestation of".
According to several authors [12, 13, 14, 15], a variable occurrence of ascites in patients with struma ovarii, ranging from 17%% to 33.3 %, has been observed and it is thought that struma ovarii should be included in the differential diagnosis of a pelvic mass that presents with ascites, hydrothorax and elevated CA125 tumour marker [16].
Transgenic wild tobacco plants (Nicotiana attenuata) expressing heterologous genes coding for antimicrobial peptides displayed an erratic and variable occurrence of transgene silencing.
8 Dependent variable: occurrence of a fatal or non-fatal CV event.
CHARGE syndrome is a multiple congenital anomaly syndrome with variable occurrence of Coloboma, Heart defects, Atresia of choanae, Retardation of growth or development, Genital hypoplasia, and Ear abnormalities and deafness.
These computed results reveal that the initial fracture pressure has complex distribution, and changes with variable occurrence of natural fracture.
Changes in the cosmic ray and heliomagnetic components of space climate, 1428 2005, including the variable occurrence of solar energetic particle events, Adv.
In this study logistic regression is used to estimate the correlation between the dependent variable (occurrence of debris flow) and independent variables (influencing attributes) by evaluating probabilities using a logistic function.
The variable occurrence of nausea, and of phonophobia in conjunction with photophobia may be an important factor in clinical studies where attacks are diagnosed based on these clinical features.
*Odds ratios calculated by using dependent variable "occurrence of at least one medication error" with patients as unit of analysis.
A full factorial model with factors Year (2001 vs. 2002) and Season (cold-dry vs. warm-rainy) was fitted to each response variable (occurrence of rotavirus, enterovirus and astrovirus; abundance of TC, FC, and FE) separately.
Dependent variable: occurrence of insomnia (yes-no), independent: ASSQ (The High-Functioning Autism Spectrum Screening Questionnaire) or SDQ (The Strengths and Difficulties Questionnaire) score, controlling for age of the child.
