I have measurements from two tablet sensors. The first sensor measures the touch pressure applied to the tablet and the second sensor is the acceleration of the tablet (in z direction). The sensor data are stored in csv files where the first column contains the timestamp (in milliseconds) and the second column contains the sensor data (either touch pressure or acceleration). I have uploaded the two sensors files: https://1drv.ms/f/s!AlkQuYgB1McYgudFUrpMzMopUr2wVw
Now I would like to investigate if there exists a correlation between touch pressure and acceleration. I could just calculate the cross-correlation or plotting the pressure against the acceleration (and perhaps add a linear regression line).
The problem is that the acceleration measurements have a more or less constant sampling rate but for the pressure I have not a constant sampling rate. That means that the number of measurements for acceleration and pressure is also not the same (and the timestamps are therefore also not the same).
How can I still calculate the correlation and producing a accleration vs. pressure plot? I thought about a interpolation of the accleration measurements to the timestamps of the pressure readings but I don't know what type of interpolation to use (linear or cubic seems not to be right). Perhaps there is a better way of doing it.
Here are the plots of the two sensors: