The Screening Interview
Usually there are a series of interviews before a job offer is made. The first, called a screening interview, lasts about 30 minutes to an hour. For larger companies, a human resources officer usually conducts this interview. Some screening interviews are conducted over the phone.
Often the questions are designed to query about your past performances and skills. The rationale is that your successes in a past situation, whether directly related to the job or not, will probably be a good indicator of your performance in the future.