How to select a random sample from all your data [trick]

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The other day, I got a text message (SMS) from one of our readers. It read,

How to select random samples from data in Excel?

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.

Random samples needed from this data set

Now, if you just want to select any 10 (or x number of) random items from this list, then your job would very simple.

  1. Shuffle (or randomly arrange) this list
  2. Just pick first 10 items

But our problem is to get 2 random samples per user.

Selecting random samples from data

Follow below steps.

  1. Add an extra column and fill it with =RAND() formula. This generates random fraction between 0 and 1.

    Add RAND() function to the adjacent column

  2. Create a pivot table from this data (tutorial: How to create a pivot table?)
  3. Add User ID & Case ID as Row labels and Random as value field.
    Pivot table layout for selecting random samples
  4. Click on the filter icon on Case ID column, choose Value filter > Top 10
  5. Filter for top 2 random values. (related: Filter top 10 values in pivot tables – how to?)

    Pivot Table value filters - filtering top 2 values

  6. Adjust report layout (Table layout, no sub-totals, no grand totals)

    Report layout to show just the samples and nothing else

  7. Done!

Final random samples - easy and awesome.

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.

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13 Responses to “Convert fractional Excel time to hours & minutes [Quick tip]”

  1. Debraj Roy says:

    Hi Purna..

    Again a great tip.. Its a great way to convert Fractional Time..
    By the way.. Excel has two great and rarely used formula..

    =DOLLARFR(7.8,60) and =DOLLARDE(7.48,60)

    basically US Account person uses those to convert some currency denomination.. and we can use it to convert Year(i.e 3.11 Year = 3 year 11 month) and Week(6.5 week = 6 week 5 days), in the same manner...

  2. Jason says:

    This doesn't work for me. When applying the custom format of [h]:mm to 7.8 I get 187:12

    Any ideas why?

    • Hui... says:

      @Jason
      7.8 in Excel talk means 7.8 days
      =7.8*24
      =187.2 Hrs
      =187 Hrs 12 Mins

      If you follow Chandoo's instructions you will see that he divides the 7.8 by 24 to get it to a fraction of a day

      Simple, assuming the fractional time is in cell A1,

      Use below steps to convert it to hours & minutes:

      1. In the target cell, write =A1/24
      2. Select the target cell and press CTRL+1 to format it (you can also right click and select format cells)
      3. Select Custom from “Number” tab and enter the code [h]:mm
      4. Done!

  3. WhoKnows says:

    Hi, sorry to point this out but Column C Header is misspelt 'Hours Palyed'

  4. abhishek malik says:

    good one

  5. Julia says:

    So how do I go the other way and get hours and minutes to fractional time?

    • Chandoo says:

      If you have 7.5 in cell A1,

      - Use int(A1) to get the hours.
      - Use mod(A1,1)*60 to get minutes.

      If you have 7:30 (formatted as time) in A1

      - Use hours(a1) to get hours
      - Use minutes(a1) to get minutes.

      • Paula says:

        I had the same issue. You can solve it by changing the format as described above:

        Right click cell > Format Cells > (In Number tab) > Custom > Then enter the code [h]:mm
        ([hh]:mm and [hhh]:mm are nice too if you want to show leading zeros)

        • Jack Scarce says:

          Thanks guys, these are the tips I'm looking for.
          ...dividing the number of minutes elapsed by the percent change is my task - "int" is the key this time

  6. Srikanth says:

    It doesnt work for greater than 24 hours
    It returns 1:30 for 25.5 hours. It should have returned 25:30

    Ideally I would right function as
    =QUOTIENT(A1,1)&":"&MOD(A1,1)*60

    • Paula says:

      Sorry, replied to wrong comment....

      ----
      I had the same issue. You can solve it by changing the format as described above:

      Right click cell > Format Cells > (In Number tab) > Custom > Then enter the code [h]:mm
      ([hh]:mm and [hhh]:mm are nice too if you want to show leading zeros)

  7. Daniel says:

    Clever use of MOD here to extract the decimal part of a number. Divide a number containing a decimal by 1 and return the remainder. Humm. Very clever.

  8. Tomer says:

    Thanks very much, extremely useful !

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