Quiz marks were 55, 60, 65, 70 and 75 each weighted equally toward the course grade. A student mistakenly averages only the lowest and highest marks. By how many marks does this wrong mid‑range exceed the true mean mark?
Q1. Quiz marks were 55, 60, 65, 70 and 75 each weighted equally toward the course grade. A student mistakenly averages only the lowest and highest marks. By how many marks does this wrong mid‑range exceed the true mean mark?
Answer: 0
Explanation: True mean = (55+60+65+70+75)/5 = 65; mid-range = (55+75)/2 = 65 as well, so the difference is 0.