Properly compute the variance when there is an offset

measure-analysis/measure-analysis.py

@@ -359,7 +359,7 @@ class MeasureSet:
             for x, p in enumerate_prop:
                 var += p * x**2
             var /= sum_prop
-            var -= avg**2
+            var -= (avg + self.middle)**2
 
             self.avg.append(avg)
             self.var.append(var)

measure-analysis/measures/measure-report.md

@@ -56,10 +56,10 @@ Min                           | Max                           | Avg
 
 **Common test metadata:** Board name: Slate, Linux kernel version: 4.19, Boot Parameters: isolcpus, Interval: 139us, ETF qdisc delta: 200us, Task priority: 99, Device and processor load: ssh, Test duration: 0h17
 
-Min         | Max        | Avg        | Var         
------------ | ---------- | ---------- | ------------
-**jitter**  | **jitter** | **jitter** | **jitter**  
--100.0000us | 186.0000us | 39.1402us  | 17980.1462us
+Min         | Max        | Avg        | Var       
+----------- | ---------- | ---------- | ----------
+**jitter**  | **jitter** | **jitter** | **jitter**
+-100.0000us | 186.0000us | 39.1402us  | 152.1151us
 
 ![alt text](graphs/packet_jitterjitter.png "packet_jitter Graph")