Value of mean and stdDev of LogNormalShadowing in Mixim

[cirom]

Hi,
I have to do the simulations on communications between nodes with the
protocol 802.15.4Narrow . During the simulation i have to insert the
interference of type LogNormalShadowing. What does it mean and what
values i have attributed to Mean and stdDev?

Thanks

[cirom]

Someone who knows a range of values in decibel attributed to Mean and
stdDev?
Tanks