To calculate sample mean and sample standard deviation for the given set of data. Formulating null and alternative hypothesis to test the claim that the sleeping pill is effective at a 1% level of significance.
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 50 randomly selected customers said that they were satisfied with the service.
At the 5 percent level of significance, can we infer that the difference in the level of satisfaction with service between the two branches is wider than 5 p.c. points?