In deck statistics, there are two charts for reviewing: time and number. The user toggles between them with a checkbox but the iOS way is to be able to horizontally scroll over between them. This would eliminate the need for the checkbox, making each chart clearer.
I’m afraid I’m not super-fond of this idea - it makes the implementation more complex (now we need to render two graphs at the same time), and it makes it harder to compare differences in count vs time.
How does the comparison between time and cards work visually? Just trying to understand the motivation for doing that. I guess you’d want to know if you’re taking a longer time to review cards, but you need to weigh that up against how many cards you reviewed. To do that well you’d just want a graph of time-per-card over time rather than time per day. I think you’d expect to see a strong correlation of time with number and if you didn’t, what would you do? Use advanced search to see what you reviewed on that day and consider cards for rewriting?
Maybe it’s just the toggling between charts with a checkbox that looks strange next to the time ranges radio boxes. Perhaps moving it under the chart. Sorry for using this space to think aloud!