A lot of those tests were people not presenting with COVID-19 symptoms though. Think of all the asymptomatic people who were getting tested; that group had a much lower test positivity rate than 55%, thus bringing the average down. For people who had all the right symptoms, it was higher than 55%.
That effect doesn't seem like it would skew a larger difference between Alberta and NYC test positivity rates. If anything, that would depress Alberta test positivity rates more than NYC ones, since we've got more spare testing capacity for people without all the right symptoms.
