The first four moments of a distribution about the value 3 are -2,10,-25,50.
Calculate moment about mean, moment about origin, moment about the value 5Solution:The first four moments of a distribution about the value 3 are
`M_1=-2`
`M_2=10`
`M_3=-25`
`M_4=50`
Find Central moments using Moments about the value 3First Central Moment`m_1=0`
Second Central Moment`m_2=M_2-M_1^2`
`=10-(-2)^2`
`=10-4`
`=6`
Third Central Moment`m_3=M_3-3M_2M_1+2M_1^3`
`=(-25)-3*10*(-2)+2*(-2)^3`
`=(-25)+60-16`
`=19`
Fourth Central Moment`m_4=M_4-4M_3M_1+6M_2M_1^2-3M_1^4`
`=50-4*(-25)*(-2)+6*10*(-2)^2-3*(-2)^4`
`=50-200+240-48`
`=42`
Now, find `bar x``M_1=bar x-A`
`-2=bar x-3`
`bar x=-2+3`
`bar x=1`
Find Moment about origin using Central momentsFirst Moment about origin`v_1=bar x`
`v_1=1`
Second Moment about origin`v_2=m_2+v_1^2`
`=6+1^2`
`=6+1`
`=7`
Third Moment about origin`v_3=m_3+3m_2v_1+v_1^3`
`=19+3*6*1+1^3`
`=19+18+1`
`=38`
Fourth Moment about origin`v_4=m_4+4m_3v_1+6m_2v_1^2+v_1^4`
`=42+4*19*1+6*6*1^2+1^4`
`=42+76+36+1`
`=155`
Find Moment about the value 5 using Central momentsFirst Moment about the value 5`M_1=bar x-A`
`=1-5`
`=-4`
Second Moment about the value 5`M_2=m_2+M_1^2`
`=6+(-4)^2`
`=6+16`
`=22`
Third Moment about the value 5`M_3=m_3+3m_2M_1+M_1^3`
`=19+3*6*(-4)+(-4)^3`
`=19-72-64`
`=-117`
Fourth Moment about the value 5`M_4=m_4+4m_3M_1+6m_2M_1^2+M_1^4`
`=42+4*19*(-4)+6*6*(-4)^2+(-4)^4`
`=42-304+576+256`
`=570`
This material is intended as a summary. Use your textbook for detail explanation.
Any bug, improvement, feedback then