I am searching in a shapefile, quantitative data, for an assignment for the entire last weeks and even today. But I am unable to find it. I could find only shapefiles but not contain any field that can be quantified using graduated colours.
Check the datatype of the field. If you see numbers in a field that has TEXT datatype, then you can create a new Field with appropriate numeric (LONG/ DOUBLE) datatype. Then Calculate Field to get the values from corresponding TEXT field to LONG/DOUBLE field.
This new field can then be symbolized using Graduated Color/Symbol.