The purpose of a study by Damm et al. (A-17) was to investigate insulin sensitivity and insulin secretion in women with previous gestational diabetes (GDM). Subjects were 12 normal-weight glucose-tolerant women (mean age, 36.6 years; standard deviation, 4.16) with previous gestational diabetes and 11 controls (mean age, 35 years; standard deviation, 3.3). Among the data collected were the following fasting plasma insulin values (mmol/L). Use the Mann–Whitney test to determine if you can conclude on the basis of these data that the two populations represented differ with respect to average fasting plasma insulin level.

Controls Previous GDM Controls Previous GDM 46.25 30.00 40.00 31.25 40.00 41.25 30.00 56.25 31.25 56.25 51.25 61.25 38.75 45.00 32.50 50.00 41.25 46.25 43.75 53.75 38.75 46.25 62.50 Source: Data provided courtesy of Dr. Peter Damm.