# NeoCal for Pocket PC User Guide

### Statistical Registers

This application uses the statistical registers and performs one- and two-variable statistical calculations such as mean, standard deviation, and linear regression. The statistical registers are represented by the , , , , , and buttons. However, these registers are not modified using the button, rather, data is accumulated into these registers by using:

- to clear the statistical registers.
- to accumulate a data point into the statistical registers. The data point can be either a single x value or an (x, y) pair. The number of accumulated data points is displayed. As with all NeoCal operations, the y value is entered before the x value.
- to remove a data point from the statistical registers. This is useful for correcting mistakes.

The accumulated statistics can be recalled by simply pressing these buttons:

- recalls the number of data points accumulated.
- recalls the summation of the x values.
- recalls the summation of the squares of the x values.
- recalls the summation of the y values.
- recalls the summation of the squares of the y values.
- recalls the summation of the products of the x and y values.
- recalls the summation of the x values into the x register and the summation of the y values into the y register.

The Statistical dialog displays the current values of all the summary registers used by the statistical calculations. Use the Preferences dialog to assign a section of the display for quicker access to this dialog.

Let's enter some data,

- Press to clear the statistical registers.
- Press (in RPN mode, use ) to accumulate the first data point.
- Press to accumulate the second data point.
- Press to accumulate the third data point.
- Press to accumulate the fourth data point.
- Press to recall the sum of the x values (245).
- Press to recall the sum of the squares of the x values (17,725).
- Press to recall the number of accumulated data points.