Answer:
Step-by-step explanation:
From the information on 60 students we write frequency distribution as
x 1 2 3 4 5 6 7 total
f 13 22 15 6 3 0 1 60
C 13 35 50 56 59 59 60
xf 13 44 45 24 15 0 7 148
x^2f 13 88 135 96 75 0 49 456
Mean = 2.67
Var = 445.92
Std dev = 21.21
I quartile = 2
III quartile = 3
20% have atmost 1