Exercise: Create a true ratio of units to area for each centre type

This exercise is provided to allow potential course delegates to choose the correct Wise Owl Microsoft training course, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.

The answer to the exercise will be included and explained if you attend the Wise Owl course listed below!

Category ==> SSAS - tabular  (29 exercises)
Topic ==> Measures  (3 exercises)
Level ==> Harder than average
Course ==> SSAS - Tabular Model
Before you can do this exercise, you'll need to download and unzip this file (if you have any problems doing this, click here for help).

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If you haven't already done so, run the SQL script in the above folder in SQL Server Management Studio to generate a database (not for commercial use or copying) called MAM

Again if you haven't already done so, create a new project called BaseModel, and import the following tables: tblAnimal, tblCentre, tblCentreType, tblPos, tblProduct, tblQuadrant, tblRegion, tblSpecies, tblStore, tblTown, tblTransaction.  Delete any measures already created.

Create the following measures:

Name What it shows
AverageMetres The average square metres area for the filter context.
AverageUnits The average number of units for the filter context.

This should allow you to create the following pivot table:

Average metres and units

The average square metre area and number of units for each shopping centre type.

 

Create a measure called FalseAverage which divides the average metres by the average units, and show this in your pivot table:

False average

The true average for any cell should be [the total square metres for that cell's filter context] divided by [the total number of units for that cell's filter context]

Now create a measure called TrueAverage which uses the AVERAGEX function to work out the true average ratio:

True average

Notice that the figures are slightly different in each case.

The Shopping Centre row is returning an error because the Market Quay centre has 0 units (at least, according to the MAM database), so we're getting a divide-by-zero error.  To get round this, amend your true average to omit any centres where the number of units equals 0 to get:

True average with error corrected

The final figures: retail parks have much larger average unit sizes than factory outlets.

If you want to keep a copy of what you've done, use DAX Editor to create a copy of your measures with extension .dax called Dodgy stats, and save your workbook with the same file name.

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