Mean = 𝑚1
′ =10, variance = 𝑚2 =15, coefficient of skewness = 𝛾1 = +1, coefficient of kurtosis is 𝛽2 = 4.
First moment about the origin is
Mean = 𝑚1
′ = 10.
Next,
𝑉𝑎𝑟𝑖𝑎𝑛𝑐𝑒 = 𝑚2 = 15=
∑ 𝑥
2
𝑛
− (
∑ 𝑥
𝑛
)
2
.
Second moment about the origin is
𝑚2
′ =
∑ 𝑥
2
𝑛
= 𝑚2 + 𝜇1
2 = 𝑉𝑎𝑟𝑖𝑎𝑛𝑐𝑒 + (
∑ 𝑥
𝑛
)
2
= 15 + 102 = 𝟏𝟏7
Coefficient of skewness is +1:
𝛾1 = +1 =
𝑚3
𝑚2
3
2
→ 𝑚3 = 𝑚2
3
2 = 16
3
2 = 64
Coefficient of kurtosis is 4:
𝛽2 = 4
𝑚4
𝑚2
2 = 4 → 𝑚4 = 4(16)
2 = 1024
Third moment about the origin is
𝑚3
′ = 𝑚3 + 3𝑚2𝑚1
′ + 𝑚1
′ 3 = 64 + 3(16)(10) + 103 = 𝟏𝟓𝟒𝟒
Fourth moment about the origin is
𝑚4
′ = 𝑚4 + 4𝑚3𝑚1
′ + 6𝑚2𝑚2
′ + 𝑚1
′ 4 = 1024 + 4(64)(10) + 6(16)102 + 104 = 𝟐𝟑𝟏𝟖𝟒
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