a researcher has collected data regarding sales made on zara's mobile app. they are interested in investigating whether consumers who subscribe to zara's weekly newsletter spend more than consumers who do not. in order to do this, they will use two variables: subscribed - records whether the consumer has subscribed to the weekly newsletter (categorical - 'yes' or 'no') sales volume - records the dollar amount that the consumer spent on the zara mobile app (continuous - exact value) which test would be most appropriate for investigating this relationship? group of answer choices