Is there a difference in body weight (kg) between participants who lift weights versus participants who do not lift weights?

Is there a difference in mean body weight (kg) between participants who do cardio versus participants who do not do cardio?

Is there a mean difference in body weight (kg) before versus after all participants tried the low calorie diet?

Is there a difference in body weight (kg) before versus after all participants tried the keto diet?

Is there an association between student nationality (domestic versus international) and whether or not they have a scholarship (yes versus no)?

Is there difference between the current distribution of ice cream purchases versus the expected distribution (20% chocolate, 20% strawberry, 20% mango, 40% vanilla)?

relationship between hours of sleep and hours of phone use

relationship between age and years of education