Charts: using a filtered list as a data range
 

Hello, I have a column of numbers, which I would like to use as the Y axis
on a chart. I can get 5-15 numbers or rows (in the column) each day and I
have 8 months of data. I would like to filter the column according time or
have a drop down box to select month and change the chart axis to reflect
only that month. The X axis only needs to increment for every Y value. If I
have another column with incrementing numbers for each row for the X axis,
this causes a problem when I want to select only a months data for the
chart. Would appreciate any help or ideas. Thanks very much, David