How is the specificity of a screening test calculated? A) True ...

[ts19998]

How is the specificity of a screening test calculated?
 
  A) True positives/Total diseased
  B) True negatives/Total not diseased
  C) False negatives/Total diseased or 1  Sensitivity
  D) False positives/Total not diseased or 1  Specificity

Question 2

When applying epidemiology and demography to the practice of community health, how is the prevalence rate calculated?
 
  A) (Number of new cases of specified health condition during time interval/Estimated midinterval population at risk)  1,000
  B) (Number of current cases of a specified health condition at a given point in time/Estimated population at risk at same point)  1,000
  C) (Number of deaths of infants aged < 1 year during time interval/Total live births during time interval)  1,000
  D) (Number of deaths from puerperal cases during 1 year/Number of live births during same year)  100,000

[xMRAZ]

Answer to Question 1

Ans: B
Specificity (true-negative rate) is calculated as True negatives/Total not diseased. Sensitivity (true-positive rate) is calculated as True positives/Total diseased. False-negative rate is calculated as False negatives/Total diseased or 1  Sensitivity. False-positive rate is calculated as False positives/Total not diseased or 1  Specificity.

Answer to Question 2

Ans: B
Prevalence rate is calculated as (Number of current cases of a specified health condition at a given point in time/Estimated population at risk at same point)  1,000. Incidence rate is calculated as (Number of new cases of specified health condition during time interval/Estimated midinterval population at risk)  1,000. Infant mortality rate is calculated as (Number of deaths of infants aged < 1 year during time interval/Total live births during time interval)  1,000. Maternal mortality rate is calculated as (Number of deaths from puerperal cases during 1 year/Number of live births during same year)  100,000.

[ts19998]

Thank you

[xMRAZ]

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