Two different analytical methods were used to determine residual chlorine in sewage effluents.
Both methods were used on the same samples, but each came from various locations, with
differing amounts of contact time with the effluent. The concentration of Cl in mg//L was
determined by the two methods, and the following results were obtained:
(a) What type of t test should be used to compare the two methods and why?
(b) Do the two methods give
(c) Does the conclusion depend on whether the 90%, 95% or 99% confidence levels are