Define a "count of" summary field in Samples and select a field that is never empty as the field to "count". (a primary key field makes an excellent field to use for this count.)
Find all records for Product "A".
Sort your records by the value in the Strength field. If it's a floating point value where "15", "14", "10" actually represent ranges of values such as 14.5 to 15.4 for a strenght of "15" define a calculation field for this sort that rounds to the lesser number of decimal points to produe a common value for each group of records representing a specific "frequency" point in your chart.
Now you can chart the summary field and specify the "found set, grouped values when sorted" data source option for your chart.
If you have never created summary reports with sub summary layout parts, ignore the rest of this post.
If you have, it may help to picture each point on your chart as a sub summary layout part. Just like such layout parts, the current found set of records must be sorted by the "Strength" field to group records and get a count of those records for each group.
Ok thanks! I am going to give this a try and report back.
Are you the VP of FM. You have all the answers my friend, for everyone, thank you so much!