Stat 321

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Stat 321 Day 11

• Review

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Announcements

• Exam Thursday
• Review sheet on web
• Review problems and solutions on web
• Covering chapters 1, 2 HW 1-3 Lab 1-3 Quiz 1-2
• You will be supplied with formulas (sample
  online)
• You will be allowed to bring in one page of notes
• Bring your calculator

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What to Expect

• Calculation and Communication
• show steps (some only set up, partial credit)
• what does it mean, interpretation
• Dont forget about Ch. 1
• Possible
• construct an example where
• show this relationship is true
• prove this statement
• Rework quizzes, hws review labs (big ideas)

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Some things to look out for

• Language
• Frequency vs. relative frequency
• Probability vs. empirical probability
• Estimated vs. exact
• See Day 9 handout online for common confusions
• Permutations vs. Combinations
• Mutually exclusive vs. independence
• Bayes Theorem vs. Law of Total Probability

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Stop and Think Questions

• If you were to flip a coin six times, which
  sequence do you think would be most likely
  HHHHHH or HHTHTH or HHHTTT?
• Linda is 31 years old, single, outspoken, and
  very bright. She majored in philosophy. As a
  student, she was deeply concerned with issues of
  discrimination and social justice, and also
  participated in antinuclear demonstrations.
  Which of the following events do you think is
  more likely? Explain your answer.
• ALinda is a bank teller
• BLinda is a bank teller and is active in the
  feminist movement
• Evelyn Marie Adams won the New Jersey lottery
  twice in a short time period. Her winnings were
  3.9 million the first time and 1.5 million the
  second time. The New York Times claimed that the
  odds of one person winning the top price twice
  were about 1 in 17 trillion. How would you
  explain to someone that this is not a startling
  coincidence?

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Day 8, Ex 2 Randomized Response

• Technique for asking sensitive questions
• Randomly decide which question respondents will
  answer sensitive or boring
• Work backwards with probability rules to estimate
  proportions for sensitive question

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Example 2 Randomized Response

• Flip fair coin
• Heads answer sensitive question
• Tails answer boring questiondoes your home
  phone number end in even digit?
• Determine proportion of yeses
• Define events
• Yresponse is yes
• Srespondent answered sensitive question

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Example 2 Randomized Response

• Respondents are ensured confidentiality
• Can still obtain estimate for P(YS)