A US market researcher was curious if there was a difference in electric vehicle ownership rates between people living on the East coast versus those on West coast. They obtained separate random samples of500 car owners from each region. They found that 52 in the West coast sample owned an electric car compared to 38 in the East coast sample. They plan to use these results to do a two-sample z test to see if these results show a significant difference.

Which conditions for this type of test did their samples meet?

A. Individual observations in each sample can be considered independent, and the samples themselves are independent.

B. The expected counts of successes and failures are sufficiently large in each sample.

C. Both samples were randomly selected from their populations.