Hi all,

Hard to describe this question so sorry for the vague subject line...

I was recently asked to compute the mean time between failures (MBTF) for a large data table for many different items we are tracking. Simply put, I have columns of items with a daily entry and either a 0 or 1 for if the device failed. Looks something like this:

A B C D
1 Date Item 1 Item 2 Item 3
2 Jan 1 1 0 0
3 Jan 2 0 1 1
4 Jan 3 1 0 0
5 Jan 4 0 1 0
6 Jan 5 1 0 0



This goes on for years. I'd like to use VBA code or a function, if possible, to give me the average number of days between failures. For instance, Item 1 would be 2 days; etc.

Anyone have any thoughts on this? I'm a moderate -> advanced (but not expert) Excel user and can adapt VBA code but not necessarily program from scratch.

Thanks.
G