If a boy cycles 8 km at the speed of 8 km per hour, and walks another 8 km at the speed of 2 km per hour. His average speed per hour is

A. The central limit theorem B. The law of statistical regularly C. The law of inertia of large numbers D. None of the above

A. Sampling error B. Measurement error C. Coverage error D. Non-response error

A. Both (A) and (R) are true B. (A) is true, but (R) is false C. (A) is false, but (R) is true D. Both (A) and (R) are false

A. 0 B. 1 C. 0.4 D. 0.8