Check the Dual axis concept in tableau
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Naveen, thanks for the suggestion, but ..
why do you think I need the 2nd Y-axis if both measurements are in the same range?
Tableau does not allow me to select the different marks styles for different measures on the same plot.
As you dais tableau wont allow different marks for same axis in order to have different marks you need to do with dual axis 1 axis marks section would be line and other marks sections would be shapes you can combine the axis with dual axis option
That's exactly right. Definitely need a dual axis for this--one for the line and one for the circle marks.