Harlan:

Thank you so much for your help and advice.

Take care

ddd

"Harlan Grove" wrote:

DDD wrote...
....
Now, if I wanted to search sheet one (pH Readings) for all 09/01/06 values,
find the min and max and place the answer in sheet two (Min-Max) - DATE ,
MIN, MAX and then continue through all the dates available - could I not use
a lookup, or an Index/Match function ?
....

You *could* use lookup or index/match calls, but there's nothing gained
by doing so. MIN/IF and MAX/IF are all you need. This assumes you've
already entered dates in your second worksheet. If so, then you use
those date entries in the second worksheet in the conditional terms
(first arguments) of the IF function calls to compare against the
entire column of dates in the first worksheet, and you use the value
range in the first worksheet as the second argument of the IF function
calls. This produces an array of values from the first worksheet
corresponding to the dates from the first worksheet that match the
given date from the second worksheet, and FALSE for nonmatching dates.
Enclosing MIN and MAX calls then return the minimum and maximum values
for the given date. No need for lookups.