OK, I have now rebuilt this for you in version 3.3, and the solution should look like this:

Here I use instead of the node Attribute Mix the node Mix (which, by the way, is funnily named MixRGB in the list):

Alternatively, as already mentioned in the comments, you can directly multiply the value of the vertex group with the randomly generated value of Random Value:

_{(Blender 3.2+)}

OK, I have now rebuilt this for you in version 3.3, and the solution should look like this:

Here I use instead of the node Attribute Mix the node Mix.

By the way, in Blender 3.2 and 3.3 this node is called MixRGB and is located in the Color category. In Blender 3.4 there is an additional new node that explicitly mixes values. This is called Mix and is located in the category Utilities.

Alternatively, as already mentioned in the comments, you can directly multiply the value of the vertex group with the randomly generated value of Random Value:

_{(Blender 3.2+)}