FIG. 2.

Growth-inhibitory activity by age group and whether individuals were parasitemic with P. falciparum just prior to the malaria season. Box-and-whisker plots represent the smallest and largest (whiskers), the lower and upper quartiles of (top and bottom of box), and the median (horizontal line across box) growth-inhibitory activity. Growth-inhibitory activity in nonparasitemic individuals increased with age (P < 0.001). Within each age group, the median growth-inhibitory activity was higher in parasitemic than in nonparasitemic individuals, but this difference reached statistical significance only in the 2- to 4-year-old (P < 0.01) and 8- to 10-year-old (P = 0.02) age groups, as indicated by an asterisk above the bar. Sample sizes for nonparasitemic individuals were as follows: 2- to 4-year-olds, n = 68; 5- to 7-year-olds, n = 45; 8- to 10-year-olds, n = 45; and 18- to 25-year-olds, n = 46. Those for parasitemic individuals were as follows: 2- to 4-year-olds, n = 4; 5- to 7-year-olds, n = 4; 8- to 10-year-olds, n = 5; and 18- to 25-year-olds, n = 3. The nonparametric Kruskal-Wallis test was used for statistical analysis.