• A

    A convenience sample of cars parked near the gate may give a biased estimate of the proportion of cars which are from a Japanese Manufacturer.

  • B

    Different investigators may get different estimates for the proportion of cars that are red.

  • C

    The sample proportion of cars that are red is an unbiased estimate of the population proportion if the sampling method is simple random.

  • D

    A sample of 100 cars in a convenience sample is always better than a sample of 20 cars from a proper random sampling method.