Testing a Hypothesis
Null hypothesis and level of signification
P-Value
Confidence Interval
Significant Treatment Difference
Power and Sample Size
Test Statistic
Null Hypothesis
p1 = probability of positive outcome for operative group
p0 = probability of positive outcome for non-operative gruop
If H0 is true, the sampling distribution will be normal
Level of signification
Alpha represents the rejection region willing to be accepted
Probability of a type I error
Critical value
Start of the rejection region
Scaled version of the sampling distribution
Critical Value
Helps to accept of reject H0
Proportion of repeated samples under H0
If p < a there is enough evidence to reject H0
If p > a there is not enough evidence to reject H0
Constructed around the test statistic
Represents the proportion that contains the true population difference
Prove with a certain number of samples to test the true difference
Contains the whole range of values and also the proportion of the confidence interval
H0 is true
True negative: do not reject H0
False positive: reject H0 (type I error)
H0 is false
False negative: do not reject H0 (type II error)
True positive: reject H0 (power)
Power: probability of rejecting a false H0