Tikal-25 Manual - Statistical Functions

The statistics mode is entered when ∑+ is pressed. It will add the current value as a sample and display the count of collected samples. Arithmetic operators will be disabled as long as the statistics mode is active.

With 2nd ∑- the last sample will be removed, which can be repeated until the sample storage is empty. When the sample storage is empty, Statistics mode will be disengaged.

2nd x̅ computes the arithmetic mean:

x̅ =	N yi ∑ i=1
	N

2nd VAR computes the variance using N weighting for data samples:

Variance =	∑ y2i	-	(∑ yi)2
	N		N2

2nd SD calculates the standard deviation of the data using N-1 weighting for the samples entered.

Standard Deviation = √(VAR × N/(N-1))

2nd SD x² Variance - Calculates the variance using N - 1 weighting for the samples.

2nd VAR INV x² Standard Deviation - Calculates the stadard deviation of the data using N weighting for the samples.

You can review the data and a graphical display opening the additional view using the ⌥ icon on the left in the model name bar below the display.

Always clear the calculator by pressing CLR twice before entering statistical data. While "STAT" is displayed, the arithmetic functions, powers, roots, parenthesis and percent keys are locked out.