Table 3: Means, standard deviations, and item difficulties of the comprehension test.

ItemMaximum scorePretestPosttest

Please explain the differences between HIV and AIDS.61.530.57.263.590.83.60
Why is “AIDS” so life threatening for humans? Provide two reasons.20.830.39.411.790.62.90
Please name the different components of blood and their functioning.61.681.03.282.552.10.43
Put yourself in the position of a red blood cell and run through the entire circulatory system. Start in the heart and explain each station you run through. What is happening to you?40.470.72.121.501.28.38
Please explain why humans get childhood diseases (e.g., measles, mumps) only once.40.570.

Note. SD: standard deviation; ID: item difficulty.