Try to identify the independent and dependent variables in the following example studies:

1. Examining the difference between paracetamol and aspirin in the relief of pain experienced by migraine sufferers 2. Examining the effects of consultants providing full information about a surgical procedure to patients (rather than minimal information) prior to surgery on time to be discharged post surgery 3. Examining the difference between wards with matrons and those without on in-patient satisfaction 4. Examining the uptake of chlamydia screening from family doctor surgeries with and without chlamydia health promotion leaflets