Which of the following experiments uses independent samples? you want to compare the mean first-month weight gain of premature babies to that of full-term babies. so you compare the mean first-month weight gain of a random sample of premature babies to the mean first-month weight gain of a random sample of full-term babies. you want to compare the mean sat scores of students before and after they complete a new sat preparation course. so you compare the mean sat scores of a randomly selected group of students before and after they completed a new sat preparation course. you want to compare the mean first-month weight gain of a random sample of premature babies to the known us average first-month weight gain for all newborn babies.