The researchers discuss in their Power Analysis section that they estimated the effect size from the results of a small pilot study. If the impact of the use of a ball on the length of the first stage of labor was actually overestimated in the pilot study, how would this affect the estimate of the effect size used by the researchers? How would the effect size they used affect the sample size selected? How might this affect the results?

Here’s an example of how multiple regression can be useful in a research study. Sometimes it helps you understand the concept when you see it applied in a real-life scenario. In a study completed by Tussey et al. (2015), laboring women who had received an epidural were randomized into two groups and compared. One group was given routine care; the experimental group was provided with a peanut-shaped exercise ball. The ball was used to support maternal positioning that promoted spinal flexion; fetal head rotation; and widening of the pelvic inlet, outlet, and intertuberous diameter. Answer the following questions regarding this study. Tussey, C. M., Botsios, E., Gerkin, R. D., Kelly, L. A., Gamez, J., & Mensik, J. (2015). Reducing length of labor and cesarean surgery rate using a peanut ball for women laboring with an epidural. The Journal of Perinatal Education, 24(1), 16–24. doi:10.1891/1058-1243.24.1.16