Test the given problem using two sample independent Z test.
The Gibbs Baby Food Company wishes to compare the weight gain of infants using their brand versus their competitor's brand. A sample of 40 babies using Gibbs products revealed a mean weight gain of 7.60 pounds in the first 3 months after birth. The standard deviation of this sample is 2.30 pounds. A sample of 55 babies using the competitors brand revealed a mean increase of 8.8 pounds with a standard deviation of 2.90 pounds. At 95 percent level of confidence, can we close that the babies using the Gibbs product gained less weight?