Question

alejandro wants to determine the average shoe size of all of the male students in his school. which sample is likely to yield the most biased results?
every tenth boy on the schools phone list
every member of the boys basketball team
every boy in a randomly selected ninth-, tenth-, eleventh-, and twelfth-grade gym class
every fifth boy who walks through the front doors of the school in the morning

Explanation:

A biased sample does not represent the population well. The boys' basketball team is a specialized group (athletes likely having larger shoe sizes compared to the general male student population). The other options (phone list, random gym - class selection, boys at school entrance) are more likely to be random and representative.

Answer:

every member of the boys' basketball team