Interval limits are 3,4,6 og 7 and number of values in the in-
tervals are 2,3 and 4.
Mean value and standard deviation based on frequency ta-
If the data is stored as a frequency table, we cannot use the
ordinary sample routine to find the mean etc. The data is sto-
red in SDAT. Use F for frequency table.
Storing discrete table
The sample is stored as 2DAT. The data is put directly into
the matrix writer where the first column contains the values
and the second column the frequencies.