The phrase "a previous study examined" is correct and usable in written English.
It can be used when referring to research or findings from an earlier study in academic or scientific writing.
Example: "A previous study examined the effects of sleep deprivation on cognitive performance."
Alternatives: "an earlier study investigated" or "a prior study analyzed".
A previous study examined the LEA gene family in cucumber and found that one of DHN genes named CsLEA54 might facilitate the adaptation of cucumber to drought stress (Altunoglu et al. 2016).
Using whole-chromosome replacement, a previous study examined ∼43% of the yeast genome, and identified no lethal or severe growth-related incompatibility between Sp and Sc [19].
A previous study examined the transcriptomic response via Illumina sequencing of cDNA (RNA-seq) from two closely related B. cenocepacia strains, AU1054 (an epidemic strain from CF patients) and HI2424, under the same conditions as this study [29].
As to the animal model of perinatal asphyxia, a previous study examined the histology of brain regions including hippocampus at adulthood by measuring neuron density [17] and showed a loss of neurons in the CA1 of hippocampus in adult rats experienced C-section with global hypoxia.
A previous study examined videotaped recordings of resident/patient encounters and medical documentation [ 9].
A previous study examined the relationship between fitness and TL in species with different longevities.
The hemicellulose-amended incubations were performed as part of a previous study examining the impacts of timber harvesting on decomposition using identical methods as described here for cellulose.
The sample size calculation was determined using data from a previous study examining plasma vWF concentration in elective open AAA repair patients [12].
A previous study examining patients in cardiogenic shock has found that in a subgroup of ten patients, topical application of ACH to the sublingual mucosa led to an increase in the proportion of perfused capillaries, but no change in TVD [30].
As has been discussed in a previous study examining publication trends in science education (Martin and Siry 2011), the patterns in publication are in part shaped by the socio-historical development of these journals with both JRST and SE being based in the United States and RISE and IJSE being based in Australia and the United Kingdom, respectively.
A previous study examining one mutation in PON1 (rs662) found an association in fetal but not maternal Chinese samples [31].
