Tillman et al (2011), Coursework Example

In Tillman et al (2011), the alkaline phosphatase column in Table 2 addresses a research question. Does human milk fortification from the time of the first feeding significantly improves weight gain and bone mineral status in infants of <31 weeks estimated gestational age as compared with delayed or standard human milk fortification? They have used a regression model called a trajectory to represent the behavior of minerals in the body of the growing infant based on the fortification independent variable. The model is advantageous in this analysis of alkaline phosphatase because it allows researchers to see how the status of the start point impacts the outcome over many weeks. Because the trajectory model predicates a regression coefficient and the random variables impact the outcomes to some extent, the figures are statistically adjusted to reduce the impact of these incidents upon measures. In other words, because there are variations between participants and it is not a perfectly controlled experiment, the data is normalized to mitigate effects of random variation and regression toward the mean. As such, the remaining data points for alkaline phosphatase as a measure of bone mineral status is less adulterated with non-experimental variables.