You want to assess popularity (mis)calibration of a given recommender system using the popularity calibration metrics %Δ𝜉 ("Delta metrics") we discussed in the lecture.

The items in the interaction history Hu of user u have the following popularity estimates (e.g., total number of users who interacted with the item):

The items in the recommendation list Ru of user u have the following popularity estimates (using the same underlying popularity definition as for Hu):

Please calculate the popularity (mis)calibration of the recommender system for user u in terms of the %Δ𝜉 measure using the arithmetic mean for 𝜉 and reporting the result as percentage (like in the examples provided in the lecture).