statistics: sample median, means, s.d. vs sample sizeby jhson114 Tags: means, median, sample, size, statistics 

#1
Oct2305, 08:35 PM

P: 82

i have a set containing 10000 data. i took 1000 samples of size 4, 16, 64, and 1024 and took the medians, means, and stadard deviations of each size. i graphed them sd of medians vs sample size, sd of mean vs sample size, and sd of s.d. vs sample size. for sample mean, i know from a text book that:
SD of sample means = population SD / sqrt(sample size n). But it seems from the graph i created using R, sd of medians and s.d. vs sample size all have the exact same looking graph, which to me suggests that: SD of sample means, medians, and s.d. = population SD / sqrt(sample size n). Is this right? it seems a little awkward. any input will be very helpful. thank you 



#2
Oct2405, 10:25 PM

Sci Advisor
HW Helper
P: 2,483

More generally, is your question whether the "sample vs. population" formula (sample stat = population stat/sqrt(n)) applies to median and std. dev. in addition to the mean? 



#3
Oct2505, 05:57 PM

P: 82

R is just a program language kind of like matlab.
"More generally, is your question whether the "sample vs. population" formula (sample stat = population stat/sqrt(n)) applies to median and std. dev. in addition to the mean?" This is exact what i'm asking. 


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