Agreed, however the volume is pretty huge and pretty fast, so it should be statistically significant.
Yeah but you prob got the good CTR Thursday of Friday evening and are now (Sunday morning) wondering why your CTR isn't as good anymore.
Day and time of day can make huge differences especially in dating. You might have statistically relevant data, but it's only statistically relevant when it's gathered and can't necessarily be applied to any other day and time.