1) A city with 1000 citizens has a 10% prevalence of disease x ..
Screening shows sensitivity 80% and specificity 70%
How many people without disease X will be falsely diagnosed positive by this screening test..
1) 20
2) 30
3) 270
4) 300
2) A city with 1000 citizens has a 10% prevalence of disease x ..
Screening shows sensitivity 80% and specificity 70%
How many people with disease X will be missed by this screening??
1) 20
2) 30
3) 270
4) 300
1) A city with 1000 citizens has a 10% prevalence of disease x ..
Screening shows sensitivity 80% and specificity 70%
How many people without disease X will be falsely diagnosed positive by this screening test..
1) 20
2) 30
3) 270
4) 300
2) A city with 1000 citizens has a 10% prevalence of disease x ..
Screening shows sensitivity 80% and specificity 70%
How many people with disease X will be missed by this screening??
1) 20
2) 30
3) 270
4) 300
Thus, FP = Non Diseased - TN ( Those who were incorrectly identified as having the disease)
= 900 - 630
= 270 (answer 1)
Plug these values into a 4*4 table,
TP ------ FP
FN-------TN
Total has to equal 1000 (total population measured). Hence, those incorrectly diagnosed as not having the disease/ those this test misses = 20 (answer 2)
Thus, FP = Non Diseased - TN ( Those who were incorrectly identified as having the disease)
= 900 - 630
= 270 (answer 1)
Plug these values into a 4*4 table,
TP ------ FP
FN-------TN
Total has to equal 1000 (total population measured). Hence, those incorrectly diagnosed as not having the disease/ those this test misses = 20 (answer 2)
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