Is this a quantitative, qualitative, or mixed-methods study? Explain your reasoning.

Researchers collected data from a local pediatrician's office to determine factors associated with low weight gain among newborns. A survey was sent to the parents of 200 newborns that were clients over the past year,of which100 parents responded, for a response rate of 50%. Researchers noticed that about 70% of the responses were from parents of females, but the town infants seen at the hospital were 50% female/male.

The respondents decided to focus on determining whether three factors were different between infants who had healthy weight gain and those who gained less than ideal weight (variable 1): parental age (variable 2), gender (variable 3), and weight at birth (measured in pounds) (variable 4). The questions about parental age did not clarify whether it was the age of the mother or father, so whichever parent completed the survey would have provided their age.