Answer:
a.the average size of a seventh-grade class is larger and varies more than that of a kindergarten class
Explanation:
ok so we know the mean and the m.a.d of both data sets, so now all we have to do is analyze the data
so the class ranges for kindergarten is 17-21
and the class ranges for 7th grade is 25-34
here's where i prove 'a' to be the correct answer;
21-17=4
34-25=9
the ranges for 7th grade is 5 more than that of a kindergarten class making 'a' the right answer
**i know i'm not an expert but an ace, i've just been trying to become a genius, sorry :(**
good luck :)
hopefully, this helps
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