In one study, information was obtained about the useful surface of the dwellings of a set of 350 individuals. Specifically, for the individuals in the sample, the average useful area of the dwellings is 127.03 m2, with a standard deviation of 31.242 m2. Assuming that the useful surface of the dwellings is distributed as a normal one, answer the following questions. (A) Obtain a 98 per cent confidence interval for the average useful area of dwellings. Find that same interval but at a confidence level of 95% and 90%. Compare with each other the different intervals obtained. (b) Could the average floor size be considered equal to 130 m2? Use the information from the above confidence intervals and point out what level of significance you would be working with in each case