Statistical Functions; Accumulations - HP -33E Owner's Handbook Manual

Specific Features of the HP-33E 19
Keystrokes Display
(1) (LsTx] 123.4560 Summons the original
number back to the
X-register.
(9 0.4560 Only the fractional portion
of the number is displayed,
rounded here to FIX 4
display.
When [9][FRAC] is pressed, the integer portion of the number is lost.
The entire number, of course, is preserved in the LAST X register.
Statistical Functions
Accumulations
Executing the (summation) function automatically gives you several
different sums and products of the values in the X- and Y-registers
at once. In order to make these values accessible for sophisticated
statistics problems, they are automatically placed by the calculator into
storage registers.
Before you begin any calculations using the key, you should first
clear the storage registers used in accumulations by executing the
L L AR ] (clear registers) function.
When you key numbers into the X- and Y-registers and press the key,
the calculator performs the following operations in the indicated regis-
ters:
Register Operation Data
Displayed X n Numberof (x, y) entries.
) n Numberof (x, y) entries.
R, X Summation of x values.
R, 22 Summation of x? values.
Rs Sy Summation of y values.
Rs 2y? Summation of y? values.
R, 2xy Summation of products
of x and y values.