Sodium Chloride Measurements of water intake, obtained from a sample of 17 rats that had been injected with a sodium chloride solution, produced a mean and standard deviation of 31.0 and 6.2 cubic centimeters (cm3), respectively. Given that the average water intake for no injected rats observed over a comparable period of time is 22.0 cm3, do the data indicate that injected rats drink more water than no injected rats? Test at the 5% level of significance. Find a 90% confidence interval for the mean water intake for injected rats.