Test 3 Problem FFT

Pressure data relative to background pressure is taken every quarter second for 16 seconds producing 64 data points corresponding to times between 0 seconds and 15.75 seconds

It is suspected that periodic phenomena are contributing to variations in this pressure.

Identify any important sine or cosine terms contributing to this variation and their frequencies and periods and amplitudes.

Then graph the linear combination of the most important terms, superimposed on a graph of the data.

Take the difference between this function at these 64 times and the data creating a residual data vector. Test this vector for normality.
 

 
y=[   -9.4373    3.2161    5.2967    2.9761   -6.8430   -0.0374    7.2257   15.8328    9.1546 -7.3490   -2.9913  -19.0965   -9.4340   -3.7345    2.4749   -6.3982   -7.9712    7.3415    8.4246    7.1256   -0.3645  -11.2210  -17.3242  -12.9688   -4.1622   10.7102   -4.2850   -3.1927   -1.9358   14.6487   14.1757   11.2624   -2.4246   -9.3811   -5.9873   -8.0098    2.5665   -0.6184    1.8448   -1.8676    2.8954   17.1060    4.4648   -4.5872  -19.5737   -9.5261   -6.2455    0.5116    2.4759   -3.6573   -3.2943    2.4109   20.8644   18.5943    2.2224  -10.2019  -16.7347   -8.9398    6.7998    1.2489    2.1519   -4.4203   -2.5412   13.4601]