96 Section 6: Statistics Functions
File name: HP 12c Pt Converted_user's guide_English_HDP0F123E02_080207
Page: 11 of 281
Printed Date:
{
2007/8/2Dimension: 14.8 cm x 21 cm
Standard Deviation
Pressing
gv
calculates the standard deviation of the
x-value
s (
s
x
) and of the
y-value
s (
s
y
). (The standard deviation of a set of data is a measure of the dispersion
around the mean.) The standard deviation of the
x-value
s appears in the display
after
gv
is pressed; to display the standard deviation of the
y-value
s, press
~
.
Example:
To calculate the standard deviations of the
x-value
s and of the
y-value
s
from the preceding example:
Keystrokes Display
gv
4,820.59
Standard deviation of sales.
~
6.03
Standard deviation of hours
worked.
The formulas used in the hp 12c platinum for calculating
s
x
and
s
y
give
best
estimates
of the population standard deviation based on a sample of the
population. Thus, current statistical convention calls them
sample
standard
deviations. So we have assumed that the seven salespersons are a sample of the
population of
all salespersons
, and our formulas derive best estimates of the
population from the sample.
What if the seven salespersons constituted the whole population of salespersons.
Then we wouldn’t need to
estimate
the
population
standard deviation. We can
find the
true population
standard deviation (
σ
) when the data set equals the total
population, using the following keystrokes.
*
Keystrokes Display
gÖ
21,714.29
Mean (dollars)
_
8.00
Number of e 1.
gv
4,463.00
σ
x
~
5.58
σ
y
*
It turns out that if you sum the mean of the population into the set itself and find the new
s
,
computed using the formulas on page 262, that
s
will be the
population
standard deviation,
σ
, of the original set.
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Страница 1: ...HP 12c Platinum Financial Calculator User s guide H Edition 5 HP part number F2231AA 90001 ...
Страница 15: ...Part I Problem Solving ...
Страница 48: ...48 Section 3 Basic Financial Functions ...
Страница 92: ...92 Section 5 Additional Operating Features Keystrokes RPN mode Display 987z 434 65 The correct answer ...
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Страница 105: ...Part II Programming ...
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Страница 157: ...Part III Solutions ...
Страница 216: ...216 Section 14 Leasing Keystrokes RPN mode Keystrokes ALG mode Display fL12 fL 12 18 10 Annual yield to lessor ...
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Страница 231: ...Appendices ...
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