
Section 6: Functions continue101




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 xdata is {999999999, 1000000001, 1000000002}, you should
enter the xdata as {–1, 1, 2} and add redundant digits to any
xrelated answer produced.


Mean


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 :



1.

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 Xregister.



2.

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 Yregister. Simply press
X Y to bring that value into
the Xregister for use.



The easiest way to accumulate the data required for the
MEAN function is by using the
Σ+ function as described above.


Standard Deviation


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 :



1.

The sample standard deviation of x is calculated using data accumulated in the
statistical registers containing Σx, Σx^{2}, and n.
(These registers are presently defined as R11,
R12, and R16.)
The result is placed in the Xregister.



2.

The sample standard deviation of y is calculated using data accumulated in the
statistical registers containing Σy, Σy^{2}, and n.
(These registers are presently defined as R13,
R14, and R16.)
The resultant y value is placed in the Yregister. Simply press
X Y to place the y value in the
Xregister for use.

