Chapter 5, Problem 53P

FIGURE 5.22 Plasma-aldosterone concentrations in 53 Caucasian and 46 African American children. Values within the shaded area were undetectable (< 50 pmol/L). The solid horizontal lines indicate the mean values, and the broken horizontal lines indicate the mean ±se. The concept of standard error (se) is discussed in Chapter 6.

Pregnant women with gestational diabetes mellitus (GDM) are at risk for long-term weight gain and subsequent development of type II diabetes. A pilot weight loss clinical trial was conducted where women with GDM were randomized to either an active intervention using a web-based delivery or a control intervention (Nicklas et al. [3]). Women were randomized at 6 weeks postpartum and then were seen at follow-up visits at 6 months and 12 months postpartum. At 12 months postpartum, women in the active group lost a mean of 0.2 lb. with a standard deviation of 15.4 lbs.

If we assume that the change in weight from pre-pregnancy to 12 months is normally distributed, then what percent of women in the active group were at or below their pre-pregnancy weight at 12 months postpartum?

Hint: For all parts of this problem, assume that weights can be measured exactly and no continuity correction is necessary.

At 12 months postpartum, women in the control group gained a mean of 7.9 lbs. with a standard deviation of 15.3 lbs. compared with their pre-pregnancy weight.