I am in the Reports and Dashboards Module. I am at the section where the exercise is to creat a Joined Report. When I click on "Tabular Format", "Joined" is missing as an option. Did I miss a step before selecting "Joined", or is there another reason why it would be missing?

I am in the Reports and Dashboards Module. I am at the section where the exercise is to creat a Joined Report. When I click on "Tabular Format", "Joined" is missing as an option. Did I miss a step before selecting "Joined", or is there another reason why it would be missing?