This experiment should be appropriate for students in grades 10-12. Various factors can be made more complicated for older students.
Procedures Have the students determine the number of males and females in the class.
This then becomes their observed results. Thus, any child has a fifty-fifty chance of being a male or female, depending on which of the chromosomes the father contributes to him or her. This becomes your proposed results. To get your proposed results in a class of a different size, multiply the total number of students by 0.5. The deviation of observed from proposed results can then be used to determine statistically whether these results could reasonably be ascribed to errors of sampling.