Most babies admitted to the NICU are premature (born before 37 weeks of pregnancy), have low birth weight (less than 5.5 pounds), or have a medical condition that requires special care.
Independent variable. An independent variable is used in statistics to predict or explain a dependent variable. For example, Age and Gender might be used as independent variables to predict the age of death or life expectancy (dependent variables). In experimental designs, the independent variables are manipulated by the researcher (e.g., different dosages of a drug).
To reiterate, the independent variable is the thing over which the researcher has control and is manipulating. In this experiment, the researcher is controlling the food intake of the participant. The dependent variable is believed to be dependent on the independent variable.