A group of teachers from the State of Veracruz suspect that not only is the level of knowledge of natural sciences of children from rural areas of their state different from that of children from urban areas, but that it is higher. They decide to test their hypothesis with a significance level of 0.05. They decide to apply an exam to all children from urban areas, obtaining an average of mu =7.3. However, they have a problem of access to rural areas, so they decide to work with a sample of children, suppose that the sample size is 30, obtaining a sample average of 7.65, suppose a population standard deviation of 0.75.