Normal Distributions
Around the mean, normal distributions are
Symmetric
The formula to calculate a negative critical value with sigma known
=NORM.S.INV(alpha/2)
Fail to reject a null hypothesis that was false
Type II Error
In a normal distribution, these three are equal
Mean, Median, Mode
=NORM.S.INV(1-(alpha/2))
(+/-)?
Positive Z-Critical Value
The probability of a Type I error
Alpha Risk (Level of Significance = Alpha Risk)
The total area under the normal curve
1 or 100%
=T.INV(alpha/2 , degrees of freedom)
(+/-)?
Negative T-Critical Value
Reject a null hypothesis that was true
Type I Error
The probability of a single random variable, X
Zero
The formula to calculate a positive critical value with 𝘴
=T.INV (1-(alpha/2) , degrees of freedom)
=T.INV.2T (1-alpha , degrees of freedom)
The probability of a Type II error
Beta Risk
Normal distributions are defined by the
Mean and Standard Deviation
Depending on population or sample status, this value determines which distribution to use
Standard Deviation
Probability of correctly rejecting a false null hypothesis
Power Of The Test