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Finding Standard Deviation "By-Hand"
Using the lists, the calculator can simulate a
spreadsheet style
"by hand" computation of standard deviation.
(see Measures of Dispersion
for the FAST way to find standard deviation)
Problem: For
the data set {10, 12, 40, 35, 14, 24, 13, 21, 42, 30}, find the
range, the standard deviation, the variance, and the mean absolute deviation
to the nearest hundredth.
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Spreadsheet-style solution for standard deviation: |
1.
Enter the data in L1. |
2.
Create
L2
to be the
deviations,
 .
2nd LIST
→
MATH #3 mean
Using the quotes
(ALPHA +) will
create a dynamic situation where
L2
will automatically update when
L1
changes.
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3.
Create L3
to be the deviations squared
 .
Again, using the quotes
(ALPHA +) will
create a dynamic situation where
L3
will automatically update when
L2
changes.
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4.
From the HOME
screen.
Compute the sum of the squared deviations,
divide by the number of pieces of data (for
a population form), and take the square
root.
2nd LIST
→
MATH #5 sum
2nd LIST
→ OPS
#3 dim
gives the dimension (size) of the list.
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ANSWER:
population standard deviation
is 11.43
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