Jerry,
I would note the presence of blown insulation of approximately 1 1/2" in depth; and, comment that it was, in my opinion, insufficient to provide any meaningfull insulating capability. Assuming it was an older house, I would then recommend that an insulation contractor be retained to bring the insulation up to a level sufficient to reduce heat loss. But, I would not attempt to measure, calculate, nor guess the existing R factor.

If the house was relatively new, I would recommend contacting the builder and call to his attention a probable code violation for the builder to fix. In California, it might qualify as a latent defect which would extend the builder's liability to ten years from NOC.
Gary