How to find Variance ?

[#1]

Given Data Table:

Date	Month	Amt
1/1/2012	Jan	100
2/1/2012	Jan	200
15/1/2012	Jan	500
31/1/2012	Jan	800
1/2/2012	Feb	600
5/2/2012	Feb	300
10/2/2012	Feb	100
28/2/2012	Feb	150
1/3/2012	Mar	200
5/3/2012	Mar	400
15/3/2012	Mar	600
31/3/2012	Mar	800
1/4/2012	Apr	100
5/4/2012	Apr	300
20/4/2012	Apr	500
30/4/2012	Apr	700

Required Scanario:

Apr	Mar	Feb	Jan
Variance=400	Variance=850	Variance=450	Variance=0
Sum=1600	Sum=2000	Sum=1150	Sum=1600
700	800	150	800
500	600	100	500
300	400	300	200
100	200	600	100

Note: Please keep in mind that we will have to take date as a dimension

Please find attached data file as source

[#2 · Accepted solution]

If you use Sum as your first Expression:

Expression1: =Sum(Amt)

Then for caculating Variance you may use:

Expression2: =After(Column(1))-Column(1)