Why are there restrictions on the domain of a sequence when the sequence is defined as a function?

Asimple random sample of size nequals14 is drawn from a population that is normally distributed. the sample mean is found to be x overbar equals 70 and the sample standard deviation is found to be sequals13. construct a 90% confidence interval about the population mean

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9

Non-euclidean geometry was discovered when, in seeking cleaner alternatives to the fifth postulate, it was found that the negation could also be true a. true b. false