A retrospective cohort study is conducted of mortality from all causes of death wong persons occupationally exposed to asbestos from 1970 to 2000. The standard population is the population of New York State, exclusive of New York City, for the same time period. To control for age and time period, indirect standardization is used. The person- years, observed deaths, and population rates we shown below for each stratum. Person Years Age 20-29 30-39 40-49 50-59 60+ 1970-1979 1000 1000 1000 500 500 Time Period 1980-1989 500 1500 1700 1000 600 1990-1999 200 1000 1500 1500 700 Observed Deaths Age 20-29 30-39 40-49 50-59 60+ 1970-1979 2 3 3 2 5 Time Period 1980-1989 1 4 5 5 1990-1999 0 2 5 6 5 Standard Population Rates (per 1000 population year) Time Period Age 1970-1979 1980-1989 20-29 18 1.8 30-39 22 22 40-49 3.1 28 50-59 4.3 4.0 60+ 6.5 6.1 1990-1999 1.6 1.9 2.7 3.9 5.8 1) Calculate the expected number of deaths for each stratum Expected Deaths Time Period 1980-1989 1970-1979 1990-1999 Age 20-29 30-39 40-49 50-59 60+ 2) Summing across tilke period, calculate the SMR for each age stratum and for the entire study cohort. 3) Explain in a sentence the meaning of the SMR for the entire study cohort. 4) What are some of the advantages and disadvantages of using the general population of NYS, exclusive of NYC, as the comparison group for this study instead of another occupational group