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February 22nd, 2019, 12:46 PM  #1 
Newbie Joined: Nov 2014 From: Deutschland Posts: 2 Thanks: 0  Mean of means  standard deviation of mean values
Sorry if this has been asked numerous times and sorry if I describe it from an engineers point of view. Let us say I have N measurements and I calculate the mean value and the standard deviation. Okay. Now let us have M times N measurements. I could calculate now the mean value of the whole number of values and calculate the standard deviation. I additionally could calculate the mean value of the standard deviations of the M measurement series but I could  and this is my question about  calculate the standard deviation of the mean value. My question: How does this value help me? What does this value describe? For me this value seems to correct the measurement in a very strong way because a factor of 1/sqrt(M) is significant. How do I have to understand the standard deviation of the means? Doesn't this mean that I can simply subdivide a dataset of X numbers to N*M numbers and then find a pretty precise mean value and in this sense a pretty reliable measurement result? Can I profit from this trick? 
February 23rd, 2019, 11:01 AM  #2 
Senior Member Joined: Sep 2015 From: USA Posts: 2,430 Thanks: 1315  

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deviation, means, standard, values 
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