I have a "subjective variable" called "Stone", which can take 9 values. For example,
Stone: Fine grained sandstone
Medium grained sand stone
Medium to fine grained sand stone
Coarse to medium grained sandstone
Coarse grained sandstone
Now, I want to convert these 9 variables into the range of [0,1] and avoid any relative importance. Can anyone please tell me how can I do this? Thanks.