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Quizzes

Quiz 8, Module Cohort

8. Calculation of rate ratio in different age strata.

The data collected by your team yield the information:

Age Group Exposed Unexposed
Number of Cases PYO Number of Cases PYO
< 30 43 2,188 75 9,249
≥ 30 31 1,487 45 5,301
Total 74 3,675 120 14,550
  1. Calculate the rate of disease among the exposed in each age group
  2. Calculate the rate of disease among the unexposed in each age group
  3. Calculate the rate ratio in each age group
  4. Interpret your findings
  5. Does the association between SUPERCLEAN and Susser Syndrome seem to vary by age group?
Answer (a) — none:

Age Group 20 - < 30 yrs: 43/2,188 = 0.0197 (or 20 cases per 1,000 PYO's)

Age Group 30 - 40 yrs: 31 / 1,487 = 0.0208 (or 21 cases per 1,000 PYO's)

Answer (b) — none:

Age Group 20 - < 30 yrs: 75 / 9,249 = 0.0081 (or 8 cases per 1,000 PYO's)

Age Group 30 - 40 yrs: 45 / 5,301 = 0.0085 (or 9 cases per 1,000 PYO's)

Answer (c) — none:

Age Group 20 - < 30 yrs: (0.0197 / 0.0081) = 2.43

Age Group 30 - 40 yrs: (0.0208 / 0.0085) = 2.45

Answer (d) — none:

Among persons aged 20 to <30 years of age, those who are exposed to the chemicals involved in the SUPERCLEAN production for at least 6 months have a 2.43 times higher rate of developing Susser Syndrome than those who are not exposed to SUPERCLEAN production.

Among persons aged 30-40 years of age, those who are exposed to the chemicals involved in the SUPERCLEAN production for at least 6 months have a 2.45 times higher rate of developing Susser Syndrome than those who are not exposed to SUPERCLEAN production.

Answer (e) —
none:

No, the rate of Susser Syndrome is similar in both age categories.