Use the keyframe command with the -vc (valueChange) option, and pass a “rand MIN MAX” as an argument. For example, to randomize sphere.tx between 1.5 and 3.2:

float $random;

 int $n=`keyframe -q -kc sphere.tx`; 

	//total number of keyframes in tx

 for($i=0;$i<$n;$i++) {

 $random=`rand 1.5 3.2`;

 keyframe -e -at tx -in $i -vc $random sphere;

 }

To randomize all the attributes, you can write an upper loop in which you change the attribute to be randomized.