What does the “#NUM” value mean in the DataPad?

The “#NUM” value indicates there is an error in a cell's expression (formulae), or the set of data being analyzed has insufficient data points in it to calculate the required parameter, thus it outputs a non-numeric value which is given as “#NUM”.

For example, in the image below we are trying to calculate the mean heart rate from channel 2 in column 2 of the data pad for intervals of one second. As there are not enough data points to perform the calculation at the beginning of the data file and at the end of the data file in channel 2, datapad is returning “#NUM “ value in the first and last cell of the Heart Rate Mean column.