With regards to the variable names, I have just amended that. Thank you for pointing that out!
Although I agree that a normal distribution is not perfect here, observe how far the 49.5 Hz reading lies from the mean:
In[1]: (Mean[Last/@frequencies] - 49.5)/StandardDeviation[Last/@frequencies]
Out[1]: 8.57123
Regardless of choice of distribution, 8.57 standard deviations from the mean is a remarkable outlier. Which distribution would you suggest as opposed to the normal (I considered Student's T, but this was not successful)?
