Time weighted average question

Hi experts,

I am looking for some help with a weighted average function. I am trying to work out the average time taken per incident, but I wish to weight or grade the incident types, The data:

Incident Occurences Weight Weighted Value
Incident A 1 45% 0.45
Incident B 72 5% 3.60
Incident C 138 5% 6.90
Incident D 49 5% 2.45
Incident E 11 10% 1.10
Incident F 15 10% 1.50
Incident G 56 10% 5.60
Incident H 5 10% 0.50

My calculations are as follows, obviously 45% of 1 gives 0.45 as a weighted total, all of the weight %'s sum to 100%, all of the weight values sum to 22.10. I am currently dividing the weight total (22.10 by 8) as there are 8 incident types? This gives me 2.76 this is then multiplied by the total number of incidents (347) which gives me a weighted total in hours of 959 hrs.

Am I correct in my assumptions/calculations or am I looking at this the wrong way.:dunno

Any help would be greatly appreciated:cool:

Cheers,

Seals