HP 33s - Manual (Page 156)

11–12 Statistical Operations
Statistics Registers
Register Number Description
n 28 Number of accumulated data pairs.
Σx 29 Sum of accumulated x–values.
Σy 30 Sum of accumulated y–values.
Σx 2 31 Sum of squares of accumulated x–values.
Σy 2
32 Sum of squares of accumulated y–values.
Σxy 33 Sum of products of accumulated x– and
y
–values.
You can load a statistics register with a summation by storing the number (28
through 33) of the register you want in i (number
I “ ) and then storing the
summation (value I ” ). Similarly, you can press | Š ” to view a
register value — the display is labeled with the register name. The SUMS menu
contains functions for recalling the register values. See "Indirectly Addressing
Variables and Labels" in chapter 13 for more information.