Quantitative Methods 2017

1112-1113 / 1676

Test result
Real status
Fail to reject H0
(No disease)
Reject H0
(Disease)
H0 is true
(No disease)
Correct decision
TRUE negatives
P=1-a
Type I error
FALSE positives
P=a
Ha is true
(Disease)
Type II error
FALSE negatives
P=b
Correct decision
TRUE positives
P=1-b
STATISTICAL ERRORS
• If we set atoo high we increase the number of false positive tests
• If we set atoo low we increase might miss a diagnosis of disease