Difference in the level of satisfaction with service between the two branches.
A bank is comparing the quality of service given by its two most important branches. In branch A, 192 out of a random selection of 300 of its customers said that they were satisfied with the service. In branch B, 138 out of 250 randomly selected customers said that they were satisfied with the service.
Calculate approximately with 90 percent confidence the difference in the level of satisfaction with service between the two branches.