Question

100 points and brainliest for correct answer!

Answer 1

Answer B.

∑fx=1637,∑fx
2
=127663,∑f=21
x
ˉ
=Mean=
∑t
∑fx
​
=77.95
σ
2
=
∑f
∑fx
2

​
−(
x
ˉ
)
2
=
21
127663
​
−(77.95)
2
=2.987
σ=1.728