AP Stats conditions

Two sample z test for proportions

SRS

independent samples

populations more than or equal to 10n

n1phat1>10

n1(1-phat1)>10

and vice versa

One sample z test

population s.d. is known

SRS

normal distribution or n is large (>30)

Two sample z test

same as one sample z test (independent samples)

One sample t test

population s.d. is unknown

SRS

observations have a normal distribution or n is large (>40)

two sample t test

Same as one sample t test (independent samples)

One sample z test for a proportion

SRS

population is > or = 10n

np0>10

n(1-p0)>10

Regression inference

x, y are linearly related

response variables have normal dist. at a fixed value of x

same s.d. for all x values

X^2 test goodness of fit

SRS

no expected counts<1

no more than 20% of expected counts<5

X^2 test homogeneity or independence

same as X^2 test goodness of fit