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Section 6: Functions continue 101
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Note: If your data {xi} or
{yi} contains many redundant leading
digits, you should refrain from copying them into the calculator. For
example, if your x-data is {999999999, 1000000001, 1000000002}, you should
enter the x-data as {–1, 1, 2} and add redundant digits to any
x-related answer produced.
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Mean
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The MEAN function is used to calculate the mean
(arithmetic average) of x and y values accumulated in the statistical
registers. When you execute MEAN :
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1.
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The mean of x is calculated using the data accumulated in the first and last
statistical registers. (These are the registers that contain Σx and n;
presently defined as R11 and
R16.) The resultant value for mean of x is
placed in the X-register.
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2.
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The mean of y is calculated using the data accumulated in the third and last
statistical registers. (These are the registers that contain Σy and n;
presently defined as R13 and
R16.) The resultant value for mean of y is
placed in the Y-register. Simply press
X Y to bring that value into
the X-register for use.
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The easiest way to accumulate the data required for the
MEAN function is by using the
Σ+ function as described above.
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Standard Deviation
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The SDEV function is used to calculate the sample
standard deviation (a measure of dispersion around the mean) of data
accumulated in the statistical registers.
When you execute SDEV :
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1.
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The sample standard deviation of x is calculated using data accumulated in the
statistical registers containing Σx, Σx2, and n.
(These registers are presently defined as R11,
R12, and R16.)
The result is placed in the X-register.
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2.
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The sample standard deviation of y is calculated using data accumulated in the
statistical registers containing Σy, Σy2, and n.
(These registers are presently defined as R13,
R14, and R16.)
The resultant y value is placed in the Y-register. Simply press
X Y to place the y value in the
X-register for use.
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