copy-pasting a cell and finding lows and highs
 

Hello,

How can I make an excel function that copy-pastes a cell to other location
if certain criteria fulfills? (eg. copy-pastes cell B4 to C5 if A1:A20
contains word "OK")

I also need to find out how much lower at lowest the following values are
after reaching the wanted level before getting a higher or lower value.
(let's say I have a temparature of 60 F that rises to 80 F, and I need to
know how low it goes at lowest after reaching 80 before it climbs to 100 F
the next day, and how high it gets at maximum before cooling back to 60. Or
return negative value (-20 in this case) if it doesn't get to 100 before
going back to 60. I have separate columns for high and low values)

Sorry for the fuzzy and tricky question. I have been thinking this for a
while but haven't found an answer yet. My warmest thanks if you can solve the
problem!