Statistical Operations 71
*Does not apply to the HP 20b.
y
Std. Dev
Standard deviation for
y
: a measure of how dispersed the
y
data values are about
the mean.
x
Population Dev
Population Standard deviation for
x
: a measure of how dispersed the
x
data values
are about the mean, assuming the data constitutes a complete set of data.
y
Population Dev
Population Standard deviation for
y
: a measure of how dispersed the
y
data values
are about the mean, assuming the data constitutes a complete set of data.
S.E.Samp.
x
Standard error for the sample
x
: a measure of the dispersion of
x
mean, assuming
the data is a sampling of a large, more complete data set.
S.E.Samp.
y
Standard error for the sample
y
: a measure of the dispersion of
y
mean, assuming
the data is a sampling of a large, more complete data set.
Pred
x
Predicts
x
for a given hypothetical value of
y
, based upon the model calculated to fit
the data.
Pred
y
Predicts
y
for a given hypothetical value of
x
, based upon the model calculated to fit
the data.
a
The
a
coefficient for the chosen regression model, which is the slope for a linear
model.
b
The
b
coefficient for the chosen regression model, which is the
y
-intercept for a linear
model.
c
The
c
coefficient for the chosen regression model, applies only for
ax
2
+bx+c
.
Correlation
The correlation coefficient for the given (
x
,
y
) data. The correlation coefficient is a
number in the range -1 through 1 that measures how closely the calculated line fits
the data.
Covariance
A measure of how much two variables change in relation to one another.
The sum of the
x
values.
The sum of the
y
values.
The sum of the squares of the
x
values.
The sum of the squares for the
y
values.
The sum of the products of the
x
and
y
values.
Quartiles*
The boundaries of a given frequency distribution divided into four parts.
Median*
The middle value in a given frequency distribution.
Maximum*
The largest value in a given frequency distribution.
Minimum*
The lowest value in a given frequency distribution.
Table 12-1 The Statistics Menu Items
Menu Item
Description
Σ
x
Σ
y
Σ
x
2
Σ
y
2
Σ
xy
