Dear Devendra Kumar,

I have now tried to analyze your data in various ways. My observations are the following:

1: Preparation and placebo are different, but with low significance, and only if samples are taken as cohorte. This is, however, technically not valid; instead, cohortes should be either sensors or subjects. In this case differences are not statistically significant.

2: The differences between the various preparations and sensors are no smaller than the difference between preparation and placebo. This suggests that differences are within system variability.

3: All measurement series show a normal distribution, with excellent significance (all <0.01). This suggests that most variances are random.

4: Some of the measurement series show a slow change over time. This suggests a normal variation in local skin temperature, and there is no particular correlation between various input parameters.

5: The sampling rate is two seconds. This correlates with the 0.5Hz peaks in the frequency analysis, and suggests that those peaks are an artefact of the measuring interval.

6: The variances within each measurement series is within +-2%. This is within the expectable accuracy of a cutaneous temperature measurement and suggests that most of the variances are system noise.

7: Inter-series variances are within +-3%. This is well within the expectable variance between measurements taken with different sensors, in different positions, and on different individuals.

Conclusions:

- Variances cannot be distinguished from system noise.
- The frequency analysis peaks are an artefact stemming from the sample frequency (the sampling frequency will always show up as peaks in a frequency spectrum analysis).

Things that can be deduced from your experiment: Skin temperatures vary slightly over time, between individuals, sensors, and measuring positions. These deductions are hardly news.

Sorry, that's about it. If you feel I have overlooked something, feel free to point it out.

Best regards, Hans

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