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PodcastHow to select a random sample from all your data [trick]
The other day, I got a text message (SMS) from one of our readers. It read,
So today, let us learn a very easy trick to select random sample from your data.
Lets take a look at the data
Since the text message has no actual data, I made up this.
Now, if you just want to select any 10 (or x number of) random items from this list, then your job would very simple.
- Shuffle (or randomly arrange) this list
- Just pick first 10 items
But our problem is to get 2 random samples per user.
Selecting random samples from data
Follow below steps.
- Add an extra column and fill it with =RAND() formula. This generates random fraction between 0 and 1.
- Create a pivot table from this data (tutorial: How to create a pivot table?)
- Add User ID & Case ID as Row labels and Random as value field.
- Click on the filter icon on Case ID column, choose Value filter > Top 10
- Filter for top 2 random values. (related: Filter top 10 values in pivot tables – how to?)
- Adjust report layout (Table layout, no sub-totals, no grand totals)
- Done!
To see new samples
Just select any cell in the pivot table, press ALT+F5. Your pivot table will be refreshed and you get new samples.
That is just easy and awesome!
Download Example Workbook
Click here to download the example file. Refresh the pivot table (ALT+F5) to see fresh samples.
Do you sample your data?
Drawing samples, running experiments, analyzing results are life breath for many businesses. As business data is growing, these analytical skills are becoming important.
How do you draw samples? What techniques you use when analyzing the data? Please share your stories, experiences & tips using comments.
A sample of our awesome collection of Excel tips
Here is a tiny sample of our awesome Excel tips. Don’t hold back, take them all, and more.
- Introduction to Pivot Tables
- How to shuffle a list of values in Excel
- How to shuffle a list using Formulas
- How to generate a random date, phone number
- Introduction to Excel’s random functions
- Case study: Generating housie (bingo) number cards using Excel
- Game: Simulating Deal or No Deal game in Excel
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At Chandoo.org, I have one goal, "to make you awesome in excel and charting". This blog is started in 2007 and today has 450+ articles and tutorials on using excel, making better charts. 
9 Responses to “How to select a random sample from all your data [trick]”
Great tip and very easy to apply, thank you very much! How do you make the text of the cell screen blur (besides – 99?
After adding “RAND” column, we could add “rank per group” column. Then by filtering for 1 and 2, we will get random 2 rows per user.
=SUMPRODUCT(($A$2:$A$20=A2)*($C$2:$C$20>C2))+1
Is it possible for anybody to create this in VBA with a button or with the help of macro ? It shpuld give randomly 2 cases per user with one click. Please help me if you can.
First time I have tried to download a sample spreadsheet for some time – I am missing something? It is downloading as a zip file even though the shortcut shows it as http://img.chandoo.org/pivot/random-samples-thru-pivot-tables.xlsx
How do I turn the zip file back into something useful?
@Robert
Save the file instead of Opening the file
Then in Explorer rename it to random-samples-thru-pivot-tables.xlsx
Then Open from Explorer or Excel
[…] How to select a random sample from all your data […]
thanks for the trick
Hey Chandoo!
We emailed last week. I’ve been trying to download your dashboards, no luck! I just set up paypal, but doesn’t seem to be working yet, although I’ve done all they’ve asked.
Is there anyway we can do this billing directly??
I would like to get this dashboards going asap and have spent two days waiting for paypal !
Regards,
Blaine
PS- Nice looking family you have!
Is there a way of selecting the number of cases to be extracted based on the value in a cell, so that the user can decide how few or many random elements they want selected?