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Two types of errors in statistical inference
•
The null hypothesis is true, but you reject it
•
An improbable event has occurred
•
The probability is controlled through the significance level
- Type I error
- False positive
•
The probability is
a
(usually set to 5%)
•
The null hypothesis is false, but you accept it
•
The result was not ‘extreme enough’
•
Sample size not sufficient
- Type II error
- False negative
•
The probability is denoted
b
.
•
It is closely related to
power
, 1-
b