What is Noah’s mean absolute deviation?

StartFraction StartAbsoluteValue 87 minus 84 EndAbsoluteValue + (2) StartFraction StartAbsoluteValue 87 minus 85 EndAbsoluteValue + StartFraction StartAbsoluteValue 87 minus 86 EndAbsoluteValue + StartFraction StartAbsoluteValue 87 minus 90 EndAbsoluteValue + StartFraction StartAbsoluteValue 87 minus 92 EndAbsoluteValue over 6 EndFraction = StartFraction 3 + 4 + 1 + 3 + 5 over 6 EndFraction
1.33
2
2.67
3.5