Answer:
Range = 7
Mean = 7.75
Assumption: Most students will have 7 or 10 letters in their last name
Explanation:
Range = Largest - Smallest
= 10 - 3
= 7
Mean = Add the total numbers up to get a total / numbers in the series
= (3+5+2(6)+2(9)+5(7)+4(8)+5(10)) / (1+1+2+5+4+2+5)
= 7.75