Re: standard deviation accuracy question

[Anonymous Monk]

the values i got

condition 1 49.56
condition 2 43.31
condition 3 50.85
condition 4 55.09

the values excel gave

condition 1 50.73
condition 2 44.33
condition 3 52.05
condition 4 56.39

the raw data

cond1   cond2   cond3   cond4
397     360.5   372     324
322     318.5   354     305.5
350     356     358     364
346     316.5   311     320
338     330     336.5   327.5
324     296.5   297     288.5
461     444     485     432.5
477     474     461     434
432     416.5   407.5   447
373     355     365     369
386     320     342     315
412     401.5   428     397.5
475     363.5   494     515
360.5   332     343.5   339
384     363     372     405
324     324     324     330
424     388     379.5   396
319     312     345     319
454.5   344     389     345
412     372     384     381.5
387     347.5   363     340
370     338     346     317

[5mi11er]

And furthering the work of esteemed monk tlm above, the difference is explained completely by whether or not your final step divides by (N-1) or by N.

   Data Set    Div(N-1)   Div N
 ------------ ---------- -------
  condition1    50.73     49.56
  condition2    44.34     43.32
  condition3    52.05     50.85
  condition4    56.39     55.10

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Update: Which is exactly what the following posts (at least) had attempted to tell you: Re^2: standard deviation accuracy question Re: standard deviation accuracy question and Re^2: standard deviation accuracy question

-Scott

[tlm]

I agree with Excel, for the most part:

condition1 50.73
condition2 44.34
condition3 52.05
condition4 56.39

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