# Use a query like 
# select round(pmag), sum(da)/count(*), sum(dd)/count(*), count(*)
# from uredux.offsetsatepoch group by round(pmag) order by round(pmag);
# or
# select round(umag), sum(da)/count(*), sum(dd)/count(*), count(*) from uredux.offsetsatepoch group by round(umag) order by round(umag);
# to obtain input data.
set term postscript
set out "offplot.ps"
set style data lines
plot 'offsets_tmp' using 1:2 title 'alpha', 'offsets_tmp' using 1:3 title 'delta'
set xlabel "PPMX Cmag"
set ylabel "mean offset"