Explains mobile volume weighted mean calculation

Adds a dedicated section explaining the calculation of the
mobile volume weighted mean and links it from the 3D view info
text. This provides users with a clear understanding of how
this key statistic is derived and its significance.

Author: magnesj

content/3d-main-window/3DViews.md

@@ -52,7 +52,7 @@ The **Animation Progress** shows which time step you are viewing.
 
 ![](/images/3d-main-window/AnimationProgress.png)
 
-The **Info Text** shows general info about the case, the selected results, and some statistics. **Mobile Volume Weighted Mean** is the mean of the current **Cell Property** weighted by the **Mobile pore volume**. Mobile pore volume is defined in every cell as: MULTPV _*_ PORV(1-SWCR). If MULTPV data is not present, it is ignored in the equation. The same applies to SWCR data.
+The **Info Text** shows general info about the case, the selected results, and some statistics. **Mobile Volume Weighted Mean** is the mean of the current **Cell Property** weighted by the **Mobile pore volume**. For details, see [Derived Results]({{% relref "derivedresults" %}}#mobile-volume-weighted-mean)
 
 ![](/images/3d-main-window/infoBox.png)
 

content/calculated-data/DerivedResults.md

@@ -77,10 +77,22 @@ Water Flooded PV, also called _Number of flooded porevolumes_ shows the amount o
 Mobile Pore Volume **MOBPORV** is computed based on the grid cell properties **PORV**, **SWCR** and **MULTPV**.
 
 If **MULTPV** is missing, **MULTPV** is set to 1.0.
-If **SWCR** is missing, **SWCR** is et to 0.0.
+If **SWCR** is missing, **SWCR** is set to 0.0.
 
 $ MOBPORV = MULTPV * PORV * (1.0 - SWCR) $
 
+### Mobile Volume Weighted Mean
+
+The **Mobile Volume Weighted Mean** is a statistical calculation that provides a more physically meaningful average of reservoir properties by weighting each cell's contribution according to its mobile pore volume.
+
+This values is displayed as text in the [Info Box in the 3D view]({{% relref "3dviews" %}}#info-box).
+
+$ Weighted Mean = Σ(MOBPORV × Value) / Σ(MOBPORV) $
+
+Where:
+- **MOBPORV** = Mobile Pore Volume (weight for each cell)
+- **Value** = The reservoir property being averaged (e.g., pressure, saturation)
+
 ### Cell Volume
 
 The static property **riCellVolume** contains the geometrical volume of a cell.