Creating bins in Tableau - Formula Evaluation Walkthrough

Sample Data

Sales amounts for 9 transactions.

Cell	Value
A1	Sales
A2	120
A3	250
A4	430
A5	310
A6	90
A7	600
A8	470
A9	150
A10	380

Formula Trace

IF [Sales] < 200 THEN 'Low' ELSEIF [Sales] < 400 THEN 'Medium' ELSE 'High' END

Step 1: Evaluate [Sales] for row 2: 120

Step 2: Check if 120 < 200

Step 3: Assign bin 'Low' for 120

Step 4: Evaluate [Sales] for row 3: 250

Step 5: Check if 250 < 200

Step 6: Check if 250 < 400

Step 7: Assign bin 'Medium' for 250

Step 8: Evaluate [Sales] for row 7: 600

Step 9: Check if 600 < 200

Step 10: Check if 600 < 400

Step 11: Assign bin 'High' for 600

Cell Reference Map

    A   
  +-----+
1 |Sales|
2 | 120 | --> Used in binning
3 | 250 | --> Used in binning
4 | 430 |
5 | 310 |
6 |  90 |
7 | 600 | --> Used in binning
8 | 470 |
9 | 150 |
10| 380 |

The formula uses the Sales values in column A to assign bins.

Result

    A      B    
  +-------+-------+
1 | Sales | Bin   |
2 | 120   | Low   |
3 | 250   | Medium|
4 | 430   | High  |
5 | 310   | Medium|
6 |  90   | Low   |
7 | 600   | High  |
8 | 470   | High  |
9 | 150   | Low   |
10| 380   | Medium|

Each sales value is assigned a bin: 'Low' for less than 200, 'Medium' for 200 to less than 400, and 'High' for 400 or more.

Sheet Trace Quiz - 3 Questions

What bin is assigned to a sales value of 150?

A Medium

B Low

C High

D None

Key Result

IF [Sales] < 200 THEN 'Low' ELSEIF [Sales] < 400 THEN 'Medium' ELSE 'High' END

Practice

1. What is the main purpose of creating bins in Tableau?

easy

A. To create calculated fields for text data

B. To join two tables based on a key

C. To filter out null values from a dataset

D. To group continuous numeric data into ranges for easier analysis

Solution

1. Step 1: Understand what bins do in Tableau

   Bins group continuous numeric data into ranges or intervals to simplify analysis.

2. Step 2: Compare options to the bin concept

   Only To group continuous numeric data into ranges for easier analysis describes grouping numeric data into ranges, which matches bins' purpose.

3. Final Answer:

   To group continuous numeric data into ranges for easier analysis -> Option D

4. Quick Check:

   Bins = Group numeric data into ranges [OK]

Hint: Bins group numbers into ranges for simpler analysis [OK]

Common Mistakes:

• Confusing bins with filters
• Thinking bins apply to text data
• Assuming bins join tables

2. Which of the following is the correct way to create bins in Tableau?

easy

A. Right-click a numeric field and select 'Create > Bins'

B. Drag a dimension to the Columns shelf and select 'Create > Bins'

C. Right-click a text field and select 'Create > Bins'

D. Use the Data menu and select 'Create > Calculated Field'

Solution

1. Step 1: Recall the bin creation method in Tableau

   You create bins by right-clicking a numeric field and choosing 'Create > Bins'.

2. Step 2: Check each option against this method

   Only Right-click a numeric field and select 'Create > Bins' matches the correct method; others either use wrong field types or wrong menu options.

3. Final Answer:

   Right-click a numeric field and select 'Create > Bins' -> Option A

4. Quick Check:

   Create bins = Right-click numeric field > Create > Bins [OK]

Hint: Bins come from right-clicking numeric fields, not text [OK]

Common Mistakes:

• Trying to create bins from text fields
• Using the Data menu instead of field context menu
• Dragging dimensions instead of numeric fields

3. Given a numeric field 'Sales' with values from 0 to 1000, if you create bins with a size of 200, how many bins will Tableau create?

medium

A. 4

B. 6

C. 5

D. 10

Solution

1. Step 1: Calculate the number of bins using Tableau's formula

   Number of bins = floor(1000 / 200) - floor(0 / 200) + 1 = 5 - 0 + 1 = 6 bins.

2. Step 2: Confirm Tableau binning

   Tableau uses floor(value / size) * size for bin start: bins at 0, 200, 400, 600, 800 covering 0-200, 200-400, 400-600, 600-800, 800-1000.

3. Step 3: Correct the calculation

   Since max value is 1000 and bin size is 200, bins start at 0, 200, 400, 600, 800 covering up to 1000, so total bins = 5.

4. Final Answer:

   5 -> Option C

5. Quick Check:

   floor(1000/200) - floor(0/200) + 1 = 6 but last bin covers 1000-1200 which is beyond max, Tableau creates 5 bins covering data [OK]

Hint: floor(max/size) - floor(min/size) + 1 usually, but check max coverage [OK]

Common Mistakes:

• Calculating range / size = 5 without endpoint adjustment
• Confusing bin size with number of bins
• Assuming bins start at 1 instead of 0

4. You created bins on a numeric field but Tableau shows an error: 'Cannot create bins on this field.' What is the most likely cause?

medium

A. The field is a string or non-numeric data type

B. The data source is not connected

C. The bin size is set to zero

D. The field is a dimension, not a measure

Solution

1. Step 1: Understand bin creation requirements

   Bins can only be created on numeric fields. If the field is string or non-numeric, Tableau cannot create bins.

2. Step 2: Analyze error causes

   The field is a string or non-numeric data type matches the cause: field is non-numeric. Other options are less likely or unrelated to this error.

3. Final Answer:

   The field is a string or non-numeric data type -> Option A

4. Quick Check:

   Bins need numeric fields, non-numeric causes error [OK]

Hint: Bins require numeric fields; strings cause errors [OK]

Common Mistakes:

• Trying to create bins on text fields
• Assuming bin size zero causes this error
• Ignoring data source connection issues

5. You want to analyze customer ages grouped in 10-year ranges using bins. The 'Age' field ranges from 18 to 72. Which bin size should you choose to create exactly 6 bins covering all ages?

hard

A. 9

B. 11

C. 13

D. 10

Solution

1. Step 1: Recall Tableau's bin count formula

   Number of bins = floor(72 / size) - floor(18 / size) + 1. Need this = 6.

2. Step 2: Test options

   A 11: floor(72/11)=6, floor(18/11)=1 -> 6-1+1=6 [check]
   B 9: floor(72/9)=8, floor(18/9)=2 -> 8-2+1=7 ✗
   C 13: floor(72/13)=5, floor(18/13)=1 -> 5-1+1=5 ✗
   D 10: floor(72/10)=7, floor(18/10)=1 -> 7-1+1=7 ✗

3. Final Answer:

   11 -> Option B

4. Quick Check:

   floor(72/11)-floor(18/11)+1=6 [OK]

Hint: Divide range by bins, round up to cover all data [OK]

Common Mistakes:

• Choosing bin size equal to exact range divided by bins without rounding
• Ignoring that bins must cover entire range
• Assuming 10-year bins always create 6 bins regardless of range