Answer
The magnitudes are 0.084 and 2.396.
Work Step by Step
If a value is unusual, then it is more than two standard deviations far from the mean. $Minimum \ usual \ value=mean-2\cdot(standard \ deviation)=1.24-2\cdot0.578=0.084.$
$Maximum \ usual \ value=mean+2\cdot(standard \ deviation)=1.24+2\cdot0.578=2.396.$
Therefore the magnitudes are 0.084 and 2.396.
