Forum Discussion
Interpolation in Excel
Hi All, I am hoping someone can help me with an issue I have been having. I am trying to add an Interpolation sum in one of my spreadsheets but I just can't figure out how. Below is the sum: ...
PeterBartholomew1 I also use Excel 365.
I'll post an image of the table below:
I hope this makes it easier.
Ultimately I would aim at using a Lambda function to lookup the Room Cavity Ratios but for now
= LET(
CU, XLOOKUP(pw₀, pw, table_CU),
RCR₁, XLOOKUP(RCR₀,RCR,RCR,,-1),
RCR₂, XLOOKUP(RCR₀,RCR,RCR,,1),
CU₁, XLOOKUP(RCR₀, RCR, CU,,-1),
CU₂, XLOOKUP(RCR₀, RCR, CU,,1),
w₁, (RCR₂-RCR₀)/(RCR₂-RCR₁),
w₂, (RCR₀-RCR₁)/(RCR₂-RCR₁),
IF(RCR₁<>RCR₀, w₁*CU₁+w₂*CU₂, CU₁) )should work with the table as far as I have copied it in to Excel. If you choose to type in the values for RCR₁, RCR₂, CU₁, CU₂, and remove the XLOOKUPS that should work fine, though I would find it tedious and error-prone. Do you also need to interpolate across 'pw' or is that a straight lookup?
- No, the pw only tells you which values to use. I'm basically given a set of data and with this data, I have to find the appropriate values from the table. Then use interpolation to find a more accurate CU value.
- Do you need me to remove the XLOOKUPS or can you
a) use them, or
b) remove them and link to data cells- Remove them and link to data cells. I'll just manually input the data into specific cells.