Suppose that a recent article stated that the mean time spent in jail by a first-time convicted burglar is 2.5 years. a study was then done to see if the mean time has increased in the new century. a random sample of 27 first-time convicted burglars in a recent year was picked. the mean length of time in jail from the survey was four years with a standard deviation of 1.9 years. suppose that it is somehow known that the population standard deviation is 1.4. conduct a hypothesis test to determine if the mean length of jail time has increased. assume the distribution of the jail times is approximately normal.
since both ơ and sx are given, which should be used?
o σ
o sx
in one to two complete sentences, explain why?