# DAX.do quiz
> This ‘article’ is a short quiz you can use to practice DAX in your browser on the website dax.do.
- URL: https://data-goblins.com/dax-do-002
- Author: Kurt Buhler
- Published: 2023-05-28
- Topic: Semantic models
# PRACTICE DAX ON THE WEBSITE DAX.DO
*…using **practice questions for the Contoso model** to exercise writing **DAX measures** and **queries**.*
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## DAX.DO - LEARN DAX BY DOING IT
Practicing with fake data will help you make better solutions with your real data.
**Learning anything requires both using theoretical material like** [**books**](https://www.sqlbi.com/books/)** and **[**courses**](https://www.sqlbi.com/training/)** as well as regular practice.** Getting hands-on experience with things you learn helps you apply your knowledge and test assumptions. It also improves other, general skills like critical thinking, problem-solving and knowledge about common business processes.
**This is true for learning data modelling, visualisation and DAX in Power BI, as well.** For example, you can complete weekly [Workout Wednesday](https://workout-wednesday.com/power-bi-challenges/) exercises to create a new visual every week. You can also practice more freeform with [personal data projects](https://data-goblins.com/personal-data). However, sometimes it is better to have a more direct test of your knowledge. Practice questions using common or shared models are a good way to do this. However, it isn’t always easy to find sample models, and it’s cumbersome to share data or .pbix files.
[**dax.do**](https://dax.do) is a website created by sqlbi to practice DAX on two different data models from within the browser. Using dax.do, you can write and share [DAX queries](https://www.sqlbi.com/whitepapers/writing-dax-queries/) on the sample models with no extra effort required. This is an invaluable tool for testing different approaches, but also can be an excellent vehicle to deliver practice questions. I recently tried this for myself through Twitter, where I shared two practice questions. The winners - the first ones to share correct answers and queries - won a free [Data Goblins adventure map](https://data-goblins.com/goblin-market-webshop/fabric-poster-data-goblins-adventure-map). This was a fun exercise, so I decided to make it a regular thing. The exact frequency of these exercises is yet to be decided, but at least once every two weeks.
**In this article I share 3 DAX practice questions for dax.do.** Each question is incrementally harder than the previous one. They are designed for people learning tabular modelling who have already familiarised themselves with the basics of DAX.
**The first person to post in the comments of this article the correct answer and a link to a correct dax.do query will win this** [**Data Goblins ‘source control’ mug**](https://data-goblins.com/goblin-market-webshop/source-control-mug-katy-the-data-kobold)**.** I’ll send it to you for free, but I can’t pre-pay duties/import fees. You can bill me for that.
First person to post in the comments the correct answers and a link to a correct dax.do query wins this mug.
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### INSTRUCTIONS
- Go to [dax.do](https://dax.do).
- Read the below questions.
- Use the information provided and the Contoso model to answer the questions.
*I will not be able to provide clarifying information or answer questions about the below questions.*
- When ready, save your query (top-left of dax.do) and copy the link.
- Post the answer to the questions and a link to your dax.do query in the comments, below.
- If your answer is correct, I will contact you in a week to ask you to e-mail me your information so I can send you the mug.
- I will post a correct dax.do query at the bottom of the article when I post the next quiz question.
> **Note:** My focus is providing interesting and challenging questions that focus on a business problem. It is possible that for the harder questions there are more than one answer depending on how you interpret the requirements or the business logic.
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## QUIZ #002
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### QUESTION 1
*You get the 'Contoso' model, which was built by someone else. The business asks you whether the measures [Margin] and [Margin %] are the "Gross Margin" or "Standard (Std.) Margin".*
*The calculation for the Gross Margin is as follows:*
*Gross Sales = Total Units Sold * Unit Price *
*COGS = Total Units Sold * Unit Cost*
*Gross Margin = Gross Sales - COGS*
*Gross Margin Perc. = Gross Margin / Gross Sales*
*The calculation for Std. Margin is as follows:*
*Discount = Total Units Sold * Unit Discount*
*Net Sales = Gross Sales - Discount*
*Std. Margin = Net Sales - COGS*
*Std. Margin Perc. = Std. Margin / Net Sales*
**a) Do the margin measures correspond to the Gross Margin or Std. Margin?**
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### QUESTION 2
*The business say that the Margin values are too high. After investigation, they realize the "Unit Cost" does not include indirect costs of distribution. This cost is a percentage based on the weight of the product*
- *If the product is a "Download Game" subcategory, the Distribution Cost is 15.00 / Unit.*
- *The below CSV shows the distribution cost:*
*Weight,DistributionUnitCost*
*< 1 KG, 5.00*
*1-2 KG, 10.00*
*3-5 KG, 15.00*
*6-10 KG, 22.50,*
*11-25 KG, 33.50,*
*26-100 KG, 50.0,*
*101 KG+, 100*
**a) How many products fall in each of the above "Distribution Cost" categories? Ensure you account for any nulls.**
*It will help you to know that:*
- *There are **35.27 ounces in a kilogram***
- *There are **2.2 kilograms in a pound***
- *There are **1000 grams in a kilogram***
**b) Do you think that there are any data quality issues with the weight data? (Yes or No). If yes, which Product categories or subcategories have data quality issues with weight?**
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### QUESTION 3
*Calculate the [Corrected Std. Margin Perc.] using the measures from (1) and the below:*
Corrected Std. Margin:
*Distribution Cost = Total Units Sold = Distribution Unit Cost (see 2)*
*Corrected Std. Margin = Net Sales - COGS - Distribution Cost*
*Corrected Std. Margin (%) = Corrected Std. Margin / Net Sales*
*Filter out any products that should have a weight but don't.*
**a) Which product brand has the biggest difference between the corrected std. margin and the original?**
**b) Approximately how big is the difference, rounded to the nearest percent?**
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## TO CONCLUDE
**Practicing is an important part of learning.** I recently have been having fun thinking of practice questions for dax.do. For a while, I will regularly post and share quiz questions you can try to practice DAX. The first person to get a correct answer wins a prize!
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## TO CONCLUDE
**Practicing is an important part of learning.** I recently have been having fun thinking of practice questions for dax.do. For a while, I will regularly post and share quiz questions you can try to practice DAX. The first person to get a correct answer wins a prize!
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