STATS NOTES

z: 99 = 2.576

z: 95= 1.96

z:90 = 1.645

Demos Formating:

T- Tests are for MEANS

Z-Tests = PROPORTIONS; YES/NO

Z-Test format: Success, Totals

Chi-Squared: Observed, Expected

WHICH TEST?

T-test for slope: Checking for Linear Relationship

Two sample t-test: two independent groups

T-test Matched pairs: natural pair or same subject measured twice

T format = Mean + Z score( SD/ SQUARE ROOT of N)

CHI Squared : Table of Frequencies

if confidence interval includes zero: no significant difference

If confidence interval does not include zero: significant difference exists

Value of the point estimate for the mean difference? = add absolute values/ 2

Sampling means: Spread always gets smaller

Chances 3/60 are defective 0.01% odds? = (0.01)³(0.99)^57

🔥 Top 5 AP Stats FRQ response patterns you NEED to know

95 percent confident that the true mean…

Type 1: Reject H0 but H0 was true

Type 2: Fail to reject H0 (Fail to reject; null =true) but HA was true

Observational studies cannot conclude causation