infants using their formula brand vs. a competitors. A sample of 40 babies using their product revealed a mean weight gain of 7.6 lbs in the first 3 months after birth. The standard deviation of the Gibbs sample is 2.3 lbs. A sample of 55 babies using the competitors brand had a mean increase of 8.1 lbs with a standard deviation of 2.9 lbs. At the 5% significance level, can we conclude that babies using Gibbs brand gained less weight?