Question

I have these questions in applied stats, and need help. No other data than what's in the questions.

1. The sensitivity of mammogram screening varies with age but on average it's 87%. What % of false positives would you expect? Is the sensitivity of this test high or low.

2. The specificity of mammogram screening is 92%. What % of false negatives would you expect? What do you conclude from this specificity?

I want to learn how to do these but I'm kinda confused. Please show me HOW You figured these out?

Answer 1

a) sensitivity is true positive rate i.e. person has a disease and tested positve.(proportion of actual positives that are correctly identified)

so, false positives would be (100-87)=13%

sensitivity of this test is high

b) specificity is true negative rate i.e. person has not a disease and tested negative.(proportion of actual negatives that are correctly identified)

so, false negative will be 8%

this means that proportion of actual negatives that are correctly identified is 0.92