AP Stats Unit 7 concepts

What normality formula is used for categorical data (proportions)?

np ≥ 10 n(1-p) ≥ 10

What type of interval or test is used in matched-pair datasets?

T intervals and T tests

What normality formula is used for quantitative data (means)?

n ≥ 30 OR population distribution is normal OR check graphs

What is the calculator function for checking normality graphs (only for problems with means)?

2nd stat plot

What type of problem uses exclusively Z tests and Z intervals?

Categorical data/proportions

When is df = n-1 true?

Only in problems with one sample/proportion

When is t* used?

Only in problems that ask for a confidence interval

How do we find t*?

2nd VARS ----> invT

When do we use Z tests in quantitative problems (means)?

If we know σ

What is the formula to find T scores?

(x-u)/(S/sqrtN)

When do we use tcdf?

When conducting T tests only. It's used to find the p-value instead of normalcdf

How do you calculate a Z interval?

x +/- z*(s/square root of n)

How do you calculate an T interval?

x +/- t*(s/square root of n)

How do we find z*?

z = (x - μ) / (σ/sqrt of n)

How do degrees of freedom (df) affect t distributions?

Higher df = smaller variance/taller curve

What is a Type 1 error?

False positive

What is a Type 2 error?

False negative

How do we write the process of finding a p-value?

P(x=x) = P(tdf=t score) = tcdf(LB

Where do we find z*?

The last row of the table on the formula sheet