The data to the right show the average retirement ages for a random sample of workers Country A Country B in CountryA and a random sample of workers in Country B. Complete parts a and b. Sample mean 65.0 years 67.9 years Sample size 40 40 Population standard deviation 4.7 years 5.0 years E> IIIC loot cuculauu In an.\" . (Round to two decimal places as needed.) Determine the appropriate critical value(s). The critical value(s) is(are) |:|. (Round to two decimal places as needed. Use a comma to separate answers as needed.)