Refer to the situation in problem 16-24. Suppose that the following relative age frequencies in the population are known:

Age Group .....Frequency

Under 10 ......0.10

10 to 15 ......0.10

16 to 18 ......0.05

19 to 22 ......0.05

23 to 25 ......0.15

26 to 30 ......0.15

31 to 35 ......0.10

36 to 40 ......0.10

41 to 45 ......0.05

46 to 50 ......0.05

51 to 55 ......0.05

56 and over ......0.05

Define strata to be used in the survey.