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old memories/physics

t distribution and GSL random number generator t distribution with large degrees of freedom is the same as Normal (Gaussian) distribution with mean 0 and standard devitation 1 approximately.normal[x_] := PDF[NormalDistribution[0, 1], x]t[x_, nu_] := PDF[StudentTDistribution[nu]], x]Plot[{normal[x], t[x, 3], t[x, 6], t[x, 20]}, {x, -6, 6}, PlotStyle -> {Black, Gray, Blue, Red}]Five real random numbers x0 from the Gaussian distribution (0,1): .. 더보기
Confidence Interval and Prediction Interval Confidence Interval (CI) describes the uncertainty in $\bar Y$ as an estimate of $\mu$, where $\bar Y$ is the sample mean and $\mu$ the population(true) mean 95% CI means that the true mean value will be inside this interval with 95% probabilitySuppose repeated samples of Y_i are taken of the same size and at the same fixed values of X as were used to determine the fitted line above. Then of all.. 더보기
PhD thesis Writing the PhD thesis is so time-consuming work. Yes, definitely, it is too hard work for me. It is significantly different from master thesis. At that time, I had no idea about what I was writing and also it was written on Korean. During a whole day, just sit and type something. However, the next day, the almost everything, which was done the day before, must be modified or be deleted. Sometim.. 더보기
Tolerance How do I make something exactly? This is a very difficult question. Before studying experimental physics, I have never thought about a tolerance. But, after studying, I realized it is so important to make a sort of decision. In the CAD world, everything is perfect except a few stupid mistakes, which are usually done by myself. In the Geant4, I also have to decide the tolerance, which is called c.. 더보기