I have various EKG graphs. I need all of the maximum and minimum voltages for each period. The periods are not all the same length. The maximums and minimums all vary.
Is there any way I can do this?
Note: it'll be hard selecting chunks of data and then finding it from that because there's nearly 2500+ values for voltage per a 12 second reading.
An example of a EKG graph is attached
When you look at the graph, the maximums / minimums I'm talking about correspond to the sharp, large peaks.
thank you
If the definition of maximums is just the highest values then you could use the LARGE function to return various values. For minimums use the SMALL function.
Or did you want to capture the largest variation between a set of consecutive values?
I don't think that'll work.
maybe something with slope can help solve this? The only thing atm is defining a increase in slope for 4 consecutive data points and labeling it as max and finding decrease in slope for 4 consecutive data points at labeling it as min. (using if statement / filter / value2-value1)
put doing this returns some false values
and if possible, I need the max / mins in a chart- there's 7 ekg readings, most with over 2500+ data points. Which is a lot to go through to find the values..
please see attachments, it explains what I'm getting at a bit more-
Please keep in mind I'm excel stupid =o
I can't help when all you post is pictures
I can post the excel data
The first attachment is the data and the first graph.
The second attachment ,on sheet 2, is the only method of analyzing data someone has suggested. It's not perfect, but maybe it can help coming up with a proper formula?.. =[
please have a quick look at the pictures as well, it kinda shows what I'm trying to do =o
thank you for helping me =)
To be honest this is beyond my maths knowledge.
I can do simple cell testing along the lines of the example you posted but the result would not be a truely robust solution.
Maybe somebody else is aware of the formula to determine spikes in data series.
is there anyone I can possibly contact for help?
How about a simple matched filter? In C7 and copy down,
=IF(AND(SUMPRODUCT( {-3;-1;1;3;1;-1;-3} * (B4:B10 - AVERAGE(B4:B10))) > 6, B7=MAX(B6:B8)), B7, NA())
Microsoft MVP - Excel
Entia non sunt multiplicanda sine necessitate
Thank you Thank you!!!
I don't know how it works, but it does the job!
I copied the first reading onto a new sheet
then I added that that formula to C7 and down
Then I added =IF(ISNUMBER(C7),"MAX",NA()) to cell D7 and ran that down
then I filtered out NA() and it gives me a chart of all the maximums. It's excellent
could you help me find the corresponding minimum please?
I've attached the excel file with the filter on sheet 2. Click the filter and remove "blank, na()" and that's how it looks =)
I just need a similar one for minimum-
I don't know what "minimum" means for a dataset like that.
The filter is incorrect, sorry; it should be {-3;-1;1;6;1;-1;-3}
Microsoft MVP - Excel
Entia non sunt multiplicanda sine necessitate
After hitting a maximum, the slope is negative. The first point at which the slope becomes positive again is the minimum.
please look at the pictures ^
You mean it's the local minima that immediately follows the peak?
Microsoft MVP - Excel
Entia non sunt multiplicanda sine necessitate
yes =) that's exactly it
is this a possibility?
=IF(D7="max", MIN(B7:B10), NA())
then I can simply insert
=IF(ISNUMBER(E7),"MIN",NA())
into the adjacent column
I'm thinking this is a simple way to do it... It makes reference to the formula you provided and immediately following it, It looks for a minimum within 3 cells.. ?
See attached.
Microsoft MVP - Excel
Entia non sunt multiplicanda sine necessitate
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