I have a CV/resume question about presentations.

“I performed data collection, cleaning and analysis for two different work projects that were both submitted as abstracts (with my name as one of the authors) and were selected for presentation” and then name the two conferences.

Are there not style guidelines for the school/s that you plan to apply to? This seems to be the kind of thing that should be addressed by a template or style guide. Whatever you do, just be certain that the wording you use leaves no ambiguity or doubt as to your status vis-à-vis the papers’ authorship.

Co-author.

Congratulations! And Good Luck!

Given you’re applying to do your PhD, you should include your involvement. It relates to research you participated in and the reportage of that research. Both things that will enhance your application. You are a named author in both cases. Present the info as @marinelife suggests. The actual presentation isn’t the most important thing. It’s the research, the data you gathered and that you reported your findings to the academy. Good luck.

Edit: I wrote a paragraphe stating that you should list the talk if you were a co-author, but after subsequent reading, I have found that this is frowned upon unless you are the supervisor of the co-author who gave the talk.

If you are a co-author on the journal article that resulted from the work, you should absolutely list that.

You should describe your contributions to this project in your CV under Research Experience (or an equivalent heading), just as you should for all research projects that you have worked on.

Absolutely include it, just be clear about your part, including presenter information also so as not to be misleading.