please solve

1.Standard deviation is a measure of variability. " True C False 2. The existence of possible lurking variables is the main reason we say association does not imply causation. " True ~ False 3. Observational studies cannot have control groups. False True 4. Samples of convenience are non-probability samples. " True B. False Samples can be biased due to poor interviewing and/or poorly worded questions. ~ True ~ false 5. A. Less than " B. Equal c c. Greater than CD. Cannot be determined from given information 6. OOOOOOOOOO CA. Less than C B. Equal C. Greater than "D. Cannot be determined from given information