PERSON  POWER_USER  DATE    TIME    SENTIMENT   LOCATION    WEIGHT
Person A    Yes     3/5/2015    12:00   0.8     LA          1.5
Person A    Yes     3/5/2015    12:01   0.7     LA          1.5
Person B    No      3/5/2015    14:00   -0.5    LA          1
Person B    No      3/5/2015    15:00   0.1     LA          1
Person A    Yes     3/5/2015    16:00   0.4     LA          1.5
Person D    Yes     3/5/2015    17:00   -0.1    WA          1.5

def CalculateScore(sentiment, poweruser):
    weight = 1.5 if poweruser == "Yes" else 1.0
    return sentiment*weight

CalculateScore( !Sentiment! , !Power_User! )