Does using a cell phone while driving make an accident more likely? Researchers compared telephone company and police records to find 699 people who had cell phones and were also involved in an auto accident. Using phone billing records, they compared cell phone use in the period of the accident with cell phone use the same period on a previous day. Result: The risk of an accident was four times higher when using a cell phone. The explanatory variable in this study is O whether the subject had an auto accident. O whether the subject was using a cell phone. O the risk of an accident. O whether the subject owned a cell phone