Two alloys, A and B, are used in the manufacture of steel bars. Suppose a steel producer wants to compare the two alloys on the basis of the average load capacity, where the load capacity of a steel bar is defined as the maximum load (weight in tons) it can support without breaking. Steel bars containing alloy A and steel bars containing alloy B were randomly selected and tested for load capacity. The results are summarized in the accompanying table.

Alloy A

Alloy B

Sample size = 11

Sample size = 17

Sample mean = 43.7

Sample mean = 48.5

Sample variance = 24.4

Sample variance = 19.9

Find a 98% two-sided confidence interval for the difference between the true average load capacities for the two alloys. What is the lower limit of the confidence interval?