AP STAT last minute reminders:
Multiple Choice:
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Answer EVERY question – you DO NOT lose points for wrong answers
Do not waste too much time on one question. If you are getting stuck, skip it and come
back at the end
If you do not know how to complete a problem, try to eliminate some answers before
guessing
Free Response:
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Do not leave anything blank
o If you get stuck, at least identify a relevant formula, state the test you would use
and the conditions that go along with that test.
Organize your work – make sure that your work is legible and that your thought process
is easy to follow
Reminders:
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Binomial vs. Geometric
o Binomial refers to the probability finding a number of successes out of a fixed
number of trials
o Geometric refers to the probability of getting the first success on a particular
trial
PDF vs. CDF
o PDF refers to the probability of a particular outcome
 Used with binomial, geometric
o CDF refers to a cumulative probability
 For normal and t distributions you can set the upper and lower bound
 For Chi2 it automatically calculates the area above that given value
 For binomial and geometric it automatically calculates the area below the
given value (inclusive)
Degrees of Freedom
o One sample mean OR Matched Pairs
 df = n-1
o Two sample mean (Independent samples)
 df = n1 + n2 – 2
2
o Chi GOF
 df = number of cells – 1
2
o Chi Independence or Homogeneity
 df = (number of rows – 1)(number of columns – 1)
o Lin Reg
 df = n-2
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Conditions
o 1 proportion
 Random/ Representative
 Success/ Failure
 10% condition
o 2 proportion (conditions 1-3 must be checked for EACH sample)
 Random/ Representative
 Success/ Failure
 10% condition
 Independent samples
o 1 mean
 Random/ Representative
 Nearly Normal (show histogram)
 population is approximately normal OR large sample size so the
CLT states the sampling distribution is approximately normal
 10% condition
o 2 mean (conditions 1-3 must be checked for EACH sample)
 Random/ Representative
 Nearly Normal (show histogram)
 population is approximately normal OR large sample size so the
CLT states the sampling distribution is approximately normal
 10% condition
 Samples are independent
o matched pairs
 1 - to - 1 relationship between samples
 Random/ Representative
 Nearly Normal (show histogram)
 population is approximately normal OR large sample size so the
CLT states the sampling distribution is approximately normal
 10% condition
o Chi2
 Two categorical variables with data in counts
 Random/ Representative
 Expected cell frequencies of at least 5 (show table of expected values)
o Lin Reg
 Straight enough (Show scatterplot of original data)
 Equal variance and random scatter in residual plot (Show sketch of
residual plot)
 Nearly normal (Show sketch of histogram for residuals)