Standard deviations (SDs) are often being used
for summarizing the spread of the data from a sample. If the spread
in the data is small, then the same will be true for the standard
deviation. Underneath the calculation is illustrated with the help
of a data example.
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55
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54
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51
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55
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53
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53
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54
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52+
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Mean
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=>
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…/8 = 53.375
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SD=
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55
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(55–53.375)2
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54
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(54–53.375)2
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51
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(51–53.375)2
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55
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(55–53.375)2
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53
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(53–53.375)2
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53
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(53–53.375)2
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54
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(54–53.375)2
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52
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(52–53.375) 2+
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SD=
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………… =>…./ n−1=> √….=>
1.407885953
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Each scientific pocket calculator has a modus for
data-analysis. It is helpful to calculate in a few minutes the mean
and standard deviation of a sample.
Calculate
standard deviation: mean = 53.375 SD = 1.407885953
The next steps are required:
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Casio fx-825 scientific
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On … mode … shift … AC … 55 … M+ … 54 … M+
… 51 … M+ … 55 … M+
… 53 … M+ … 53 … M+ … 54 … M+ … 52 … M+
…shift … [x] … shift
… σxn–1
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Texas TI-30 scientific
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On … 55 … Σ+ … 54 … Σ+ … 51 … Σ+ …55 … Σ+ …
53 … Σ+ … 53 … Σ+
… 54 … Σ+ … 52 … Σ+ … 2nd … x … 2nd …
σxn–1
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Sigma AK 222 and Commodoor
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On … 2ndf … on … 55 … M+ … 54 … M+ … 51 …
M+ … 55 … M+ … 53
… M+ … 53 … M+ … 54 … M+ … 52 … M+ …
x=>M … MR
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Calculator: Electronic Calculator
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On … mode … 2 … 55 … M+ … 54 … M+ … 51 … M+
… 55 … M+ … 53 … M+ … 53
... M+ … 54 … M+ … 52 … M+ … Shift … S-var
… 1 …
= … (mean) … Shift … S-var … 3 … (sd)
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Example:
What is the mean value, what is de SD?
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5
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4
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5
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4
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5
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4
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5
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4
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