The president of Tastee Inc., a baby-food producer, claims that her company’s product is superior to that of her leading competitor because babies gain weight faster with her product. (This is a good thing for babies.) To test this claim, a survey was undertaken. Mothers of newborn babies were asked which baby food they intended to feed their babies. Those who responded Tastee or the leading competitor were asked to keep track of their babies’ weight gains over the next 2 months. There were 15 mothers who indicated that they would feed their babies Tastee and 25 who responded that they would feed their babies the product of the leading competitor. Each baby’s weight gain (in ounces) was recorded.
a. Can we conclude, using weight gain as our criterion, that Tastee baby food is indeed superior?
b. Estimate with 95% confidence the difference between the mean weight gains of the two products.
c. Check to ensure that the required condition(s) is satisfied.