A. The mean annual incomes of certified welders are normally distributed with the mean of $51,750 and a population standard deviation of $2,000. The ship building association wishes to find out whether their welders earn more or less than $51,750 annually. A sample of 100 welders is taken and the mean annual income of the sample is $52,120. If the level of significance is 0.05, what conclusion should be drawn?

B. A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 25.1 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 23.1, 29.1, 30.1, 30.1, 27.1, 34.1, and 34.1 pounds. What is the sample mean?