A baseball analyst wants to determine the average speed of a fastball thrown in the major league this season. He chooses a week at random. During that week, he will measure the speeds of a sample number of pitches. Which sample below is included in the population that he is interested in and comes closest to being random?


All pitches


All fastballs


All pitches by pitchers whose specialty is throwing fastballs


All fastballs thrown by pitchers whose specialty is throwing fastballs