HP 10bII+, User Manual

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Getting Started 32
Input Key
The
Æ
key is used to separate two numbers when using two-number functions or two-
variable statistics. The
Æ
key can also be used to enter cash flows and cash flow counts,
ordered pairs, and evaluate any pending arithmetic operations, in which case the result is the
same as pressing
4
.
Swap Key
Pressing
\«
exchanges the following:
• The last two numbers that you entered; for instance, to change the order of division or subtraction.
• The results of functions that return two values.
The
«
key toggles the item in the
Æ
register, or swaps the top two items in the
mathematical stack. This function is used to retrieve a secondary value returned during a
calculation, as well as to swap two items during a calculation.
Statistics Keys
The statistics keys are used to access summary statistics from the statistics memory registers.
When you press
]
followed by a statistics key, you can recall one of six summary statistics
with the next keystroke.
For example, press
]
followed by the
X
key to recall the sum of the
x
-values entered.
FUNC A math error has occurred (for example, division by zero).
Table 2-11 Annunciators and status
Annunciator Status
Table 2-12 Statistics keys
Keys Description
]l
Sum of the squares of the x-
values.
]i
Sum of the squares of the y-
values.
]f
Sum of the products of the x- and
y-values.
][
Number of data points entered.