X Median R Chart Formulas

QI Macros can calculate them for you!

Create an XmedianR Chart using QI Macros

  1. Select your data.
  2. Select XmedianR on QI Macros menu.
  3. QI Macros will do the math and draw the graph for you.

Go Deeper:

The XMedianR Chart works just like the XbarR chart except that it uses the median instead of the average as a measure of central tendency.

XMedianR Chart formulas for the Range and Median charts.

Range Chart Formula


X Median Chart Formula


n = number of samples in a subgroup

k = number of subgroups used to determine the average median and range

Conforms with AIAG SPC 2nd Edition

Process: Calculate, plot, and evaluate the range chart first. If it is "out of control," so is the process. If the range chart looks okay, then calculate, plot, and evaluate the X Chart.

Note: There are no known calculations for constants in an XMedianR Chart where n > 100

The XMedianR Chart is just one of the tools included in QI Macros SPC Software for Excel.

Stop Struggling with X Median R Charts!
Start creating your X Median R Charts in just minutes.

Download a free 30-day trial. Get X Median R Charts now!

Why Choose QI Macros Over Other Control Chart Software?

easy to use

Fast and Easy to Use

  • Works right in Excel
  • Create charts in seconds
  • Easy to customize & share charts
  • Free Training Anytime

proven and trusted

Proven and Trusted

  • More than 100,000 users
  • In More than 80 countries
  • Five Star CNET Rating - Virus free



  • Only $369 USD
    Quantity Discounts Available
  • No annual subscription fees
  • Free technical support