Weighted average

[Noobforever]

Hi everyone,   I wanted to calculate weighted average on the table given below

And the weights is the total count of each type and subtype. How do I calculate this in the chart (front end).

Want to calculate weigted average for each type and each subtype and display it in a table.

Type	Sub-type	Life(in months)	Count
Andriod	Touch	9	1636
Andriod	Non-Touc	20	1785
Andriod	Pen Operated	18	1161
Andriod	Buttons	11	1668
Andriod	Watches	5	1251
Andriod	Smart Glasses	15	1613
Andriod	Camera	9	1506
Andriod	Home Appliances	16	1254
Andriod	TV	14	1026
IOS	Iphone	9	1084
IOS	Ipad	8	1463
IOS	Ipods	5	1158
IOS	Headphones	14	1344
IOS	TV	12	1567
IOS	Smart devices	15	1312
Andriod	Touch	18	1263
Andriod	Non-Touc	7	1546
Andriod	Pen Operated	13	1831
Andriod	Buttons	4	1221
Andriod	Watches	8	1565
Andriod	Smart Glasses	20	1359
Andriod	Camera	13	1035
Andriod	Home Appliances	14	1122
Andriod	TV	6	1075
IOS	Iphone	10	1154
IOS	Ipad	14	1436
IOS	Ipods	20	1366
IOS	Headphones	6	1869
IOS	TV	18	1057
IOS	Smart devices	4	1282
Andriod	Touch	13	1211
Andriod	Non-Touc	5	1480
Andriod	Pen Operated	8	1941
Andriod	Buttons	18	1032
Andriod	Watches	5	1395
Andriod	Smart Glasses	11	1425
Andriod	Camera	16	1791
Andriod	Home Appliances	6	1474
Andriod	TV	8	1555
IOS	Iphone	20	1062
IOS	Ipad	9	1635
IOS	Ipods	9	1929
IOS	Headphones	6	1594
IOS	TV	14	1080
IOS	Smart devices	16	1905