Hi,

I'm sure this is the kind of problem other have solved many times before.

A group of people are going to do measurements (Home energy usage to be exact). All of them will do that at different times and in different intervals.

So what I'll get from each person is a set of {date, value} pairs where there are dates missing in the set.

What I need is a complete set of {date, value} pairs where for each date withing the range a value is known (either measured or calculated). I expect that a simple linear interpolation would suffice for this project.

If I assume that it must be done in Excel. What is the best way to interpolate in such a dataset (so I have a value for every day) ?

Thanks.

NOTE: When these datasets are complete I'll determine the slope (i.e. usage per day) and from that we can start doing home-to-home comparisons.

ADDITIONAL INFO After first few suggestions: I do not want to manually figure out where the holes are in my measurement set (too many incomplete measurement sets!!). I'm looking for something (existing) automatic to do that for me. So if my input is

{2009-06-01,  10}
{2009-06-03,  20}
{2009-06-06, 110}

Then I expect to automatically get

{2009-06-01,  10}
{2009-06-02,  15}
{2009-06-03,  20}
{2009-06-04,  50}
{2009-06-05,  80}
{2009-06-06, 110}

Yes, I can write software that does this. I am just hoping that someone already has a "ready to run" software (Excel) feature for this (rather generic) problem.