P values

According to a study on reptiles from decades ago, the mean lifespan of giant Aldabra tortoises in the wild is 87.8 years. Many of the areas where these tortoises live have become polluted with plastic waste. Because of this, a biologist claims the mean lifespan of these tortoises has decreased. To test this claim, the biologist conducted a study of 18 randomly selected, giant Aldabra tortoises in the wild. In the study, the sample mean lifespan was 84.9 years with a sample standard deviation of 12.3 years. Assume that the population of lifespans of giant Aldabra tortoises in the wild is approximately normally distributed. Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.05 level of significance, to support the claim that u, the mean lifespan of giant Aldabra tortoises in the wild, is now less than 87.8 years. (a) State the null hypothesis Ho and the alternative hypothesis H, that you would use for the test. H X