Test Report: XSPC RX120

**Vapor** · 01-11-2009, 01:20 PM

Originally Posted by skinnee

As Vapor said...it is a trendline and above or below the actual plotted data points are forecasts/predictions based on the data being plotted. It is probably close, but as to a confidence factor I could not say. I've been trying to find a way in Excel to calculate confidence factor like I can in other Statistical Analysis apps, but I have not found a method to do so yet.

With only 5 data points dictating a trendline with a (visually) low R^2 value, even the interpolative confidence level isn't great.

If you could get any data at low RPMs (400-500RPM), it'd probably go a long way toward contributing to the shape of the curve at low RPMs

In this case, I think it's close (because the rad is designed for low airflow), but in situations where a radiator can be easily airflow starved....data at very low airflow levels goes a long way toward showing the shape of the curve

Again, great review skinnee

EDIT: is it just me or are the trendlines different on the various 10CdT graphs?

**skinnee** · 01-11-2009, 01:32 PM

Originally Posted by Vapor

With only 5 data points dictating a trendline with a (visually) low R^2 value, even the interpolative confidence level isn't great.

If you could get any data at low RPMs (400-500RPM), it'd probably go a long way toward contributing to the shape of the curve at low RPMs

In this case, I think it's close (because the rad is designed for low airflow), but in situations where a radiator can be easily airflow starved....data at very low airflow levels goes a long way toward showing the shape of the curve

Well said! Yes, anytime you add data near or modify your spec limits that will start to change the regression/trendline.

Originally Posted by Vapor

EDIT: is it just me or are the trendlines different on the various 10CdT graphs?

Yes...nice catch. The single 10CdT is a Power trendline and the comparison is a 2nd order polynomial. The R^2 value is +/- 0.0007 between the two different regression/trendline types.