The way star rating is calculated is 
        (( #5 star reviews * 5 ) + ( #4 star reviews * 4 ) + ( #3 star reviews * 3 ) + ( #2 star reviews * 2 ) + ( #1 star reviews * 1 ) ) / Total number of reviews.
        Let us say below is the review distribution for a brand.
        5 stars: 388 reviews
        4 stars: 31 reviews
        3 stars: 11 reviews
        2 stars: 34 reviews
        1 star: 582 reviews
        Star rating - (388x5 + 31x4 + 11x3 + 34x2 + 582x1) / 1046 = 2.626
        On CX Reputation platform the star rating shown would be - 2.6. This calculation is applicable to all the other integrations as well.
        Trustpilot ratings are different than the standard ratings calculation. Check the 
        link.