Final answer:
The statement cannot be determined as true or false without context, and it mixes elements of myth with potential historical practices. Medea of Greek mythology was known for killing her children but not specifically for burying an illegitimate child in her backyard.
Step-by-step explanation:
The statement "Mrs. Medea killed her illegitimate child and buried it in her backyard" appears to mix elements of mythological stories and potentially historical practices. However, from the information provided, it is not possible to affirm this statement as true or false without specific context. The literature excerpts reflect the various ways infanticide and child-related crimes were viewed and incorporated into stories and events across different cultures and time periods, especially in ancient civilizations. The character Medea, known in Greek mythology, was indeed attributed with the killing of her children, but not burying an illegitimate child in her backyard. Instead, the myths associate her with other heinous acts, including sending a poisoned cloak to her rival. Moreover, the reference to cultural practices of infanticide provides historical context but does not directly corroborate the specific event in the question.