Extracting Data from X, Y charts
Thank you for your reply, and thank yuo to del whjo replied earlier, using
the slope and intercept functions as suggested I can indeed get the figure
I'm looking for. There is a problem however....
These funtions only seem to work only if the trendline is based on linear
regression, unfortunately the data from the test needs to be plotted in a
different way, I've found so far that polynomial regression seems to give the
best results and draws a trend that looks closest to what we do by hand.
In some cases a speech curve will experience what we call "rollover" i.e.
the ability of the patient to hear speech will deterioriate (rather than
increase) as the intensity of speech sounds are raised. This effect is
characteristic of neural lesions and back in the day before MRI used to be
used as part of diagnostic assessments of brain tumors amongst other things.
Its very important then that any trendline that is drawn from the data will
accurately display this rollover... My question is then, is there a way I can
use these functions or any others to get the results from the x axis with a
different sort of trendline that can reflect the above mentioned rollover
effect?
Thanks again for your help
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