DAX建议在PowerBI中生成特定的加权平均度量？

Question

I'm trying to formulate weighted average measures in PowerBi for survey data. I've currently got the following two tables (simplified):

Survey Data

ID           How would you score the service?      Do you agree with X?
---------------------------------------------------------------------------
23           Fair                                  Agree
24           Poor                                  Strongly disagree
25           Fair                                  Agree
26           Very poor                             *blank*
27           Very good                             Strongly agree

Weights

Weight         Score         Likert
-------------------------------------------------
 1             Very poor     Strongly disagree
 2             Poor          Disagree
 3             Fair          Neither agree nor disagree
 4             Good          Agree
 5             Very good     Strongly Agree

There's currently a relationship between 'surveydata'[How would you score the service?] and 'weights'[weight] .

The weighted average formula I'm trying to calculate is the following:

                (x1 * w1) + (x2 * w2) + ... (xn * wn)
Weighted Ave = ___________________________________________
                          x1 + x2 + ... xn

Where:

w = weight of answer choice
x = response count for answer choice

For the example above, I would need two measures - a weighted average for 'surveydata'[How would you score the service?] and one for 'surveydata'[Do you agree with X?] .

For the example above, the weighted average measure for 'surveydata'[How would you score the service?] should be 2.8.

Note that one of the complications is the fact that there are *blank* cells.

Can anyone suggest a way of doing this in PowerBI with calculated measures (or otherwise)?

Answer 1

You can sum the weights for each row in your SurveyData table and divide by the number rows

Weighted Ave =
DIVIDE(
    SUMX(SurveyData, RELATED(Weights[Weight])),
    COUNTROWS(SurveyData)
)

Or simply use an average function

Weighted Ave = AVERAGEX(SurveyData, RELATED(Weights[Weight]))