How to calculate Mean, Median, Mode and standard deviation in group data?

The Mean is relatively easy,
It will be easiest to explain what I am doing if I change the arangement of your columns slightly.

Column A = shortest time in the category
Column B = longest time in the category
Column C = number of e-mails in the category

Column D = C*(B+A)/2
i.e. number of e-mails multiplied by the mid-time for the category.

The mean time for e-mails is then the sum of column D divided by the sum of column C. (=2.12 for the example numbers)

I will have to think a little for the other quantities.

Mark.

Thanks alot Mark!

Looking forward to the your replies!

Cheers,
Ingen