Upgrade to Pro — share decks privately, control downloads, hide ads and more …

The M Word

jeg2
June 18, 2012

The M Word

The talk I gave to the Oklahoma Atheists in June of 2012 about math literacy.

jeg2

June 18, 2012
Tweet

More Decks by jeg2

Other Decks in Education

Transcript

  1. Math Quiz A baseball and bat together cost $1.10. The

    bat costs $1.00 more than the ball. What does the ball cost?
  2. Word Problems A baseball and bat together cost $1.10. The

    bat costs $1.00 more than the ball. What does the ball cost?
  3. Word Problems 1 Ball A baseball and bat together cost

    $1.10. The bat costs $1.00 more than the ball. What does the ball cost?
  4. Word Problems 1 Ball + 1 Bat A baseball and

    bat together cost $1.10. The bat costs $1.00 more than the ball. What does the ball cost?
  5. Word Problems = $1.10 1 Ball + 1 Bat A

    baseball and bat together cost $1.10. The bat costs $1.00 more than the ball. What does the ball cost?
  6. Word Problems = $1.10 1 Ball + (1 Ball +

    $1.00) A baseball and bat together cost $1.10. The bat costs $1.00 more than the ball. What does the ball cost?
  7. Word Problems = $1.10 1 Ball + (1 Ball +

    $1.00) A baseball and bat together cost $1.10. The bat costs $1.00 more than the ball. What does the ball cost? 1 Ball + 1 Ball + $1.00 = $1.10
  8. Word Problems = $1.10 1 Ball + (1 Ball +

    $1.00) A baseball and bat together cost $1.10. The bat costs $1.00 more than the ball. What does the ball cost? 1 Ball + 1 Ball + $1.00 = $1.10 2 Balls + $1.00 = $1.10
  9. Word Problems = $1.10 1 Ball + (1 Ball +

    $1.00) A baseball and bat together cost $1.10. The bat costs $1.00 more than the ball. What does the ball cost? 1 Ball + 1 Ball + $1.00 = $1.10 2 Balls + $1.00 = $1.10 2 Balls = 10¢
  10. Word Problems = $1.10 1 Ball + (1 Ball +

    $1.00) A baseball and bat together cost $1.10. The bat costs $1.00 more than the ball. What does the ball cost? 1 Ball + 1 Ball + $1.00 = $1.10 2 Balls + $1.00 = $1.10 2 Balls = 10¢ 1 Ball = 5¢
  11. James Edward Gray II • I’m a programmer • We

    use at least a little math in our jobs • I’m an atheist • Good atheists use a little math too • I’m not a math whiz
  12. Branches of Math • Combinatorics: dealing with combinations of objects

    • Estimation: rough calculations of value, quantity, or extent • Probability: the extent to which an event is likely to occur
  13. Math Quiz How many people would you need to gather

    to be absolutely certain (a 100% chance) that two people in the group share a birthday (month and day only)?
  14. Math Quiz: Round 2 How many people do we need

    to gather if we are willing to accept half the odds (a 50% chance) that two people in the group share a birthday?
  15. Birthday Combinatorics • Ignoring Leap Year to keep this simple…

    • The possible combinations of five different birthdays: 365 × 365 × 365 × 365 × 365 (or 3655) • The ways you can select five birthdays without repeats: 365 × 364 × 363 × 362 × 361
  16. Birthday Probability • The ratio (fraction) of events we’re interested

    in to the total possible events • Chance five people don’t share a birthday: (365 × 364 × 363 × 362 × 361) / (365 × 365 × 365 × 365 × 365) • Subtract from one to get the chance of the opposite occurrence (a birthday is shared)
  17. Chance Five People Share a Birthday 365 × 364 ×

    363 × 362 × 361 365 × 365 × 365 × 365 × 365
  18. Chance Five People Share a Birthday 365 × 364 ×

    363 × 362 × 361 365 × 365 × 365 × 365 × 365 = 0.972…
  19. Chance Five People Share a Birthday 365 × 364 ×

    363 × 362 × 361 365 × 365 × 365 × 365 × 365 = 0.972… 1 - 0.972… = 0.027…
  20. Chance Five People Share a Birthday 365 × 364 ×

    363 × 362 × 361 365 × 365 × 365 × 365 × 365 = 0.972… 1 - 0.972… = 0.027… About 3%
  21. Chance Twenty Three Share a Birthday 365 × 364 ×

    … × 344 × 343 365 × 365 × … × 365 × 365
  22. Chance Twenty Three Share a Birthday 365 × 364 ×

    … × 344 × 343 365 × 365 × … × 365 × 365 = 0.492…
  23. Chance Twenty Three Share a Birthday 365 × 364 ×

    … × 344 × 343 365 × 365 × … × 365 × 365 = 0.492… 1 - 0.492… = 0.507…
  24. Chance Twenty Three Share a Birthday 365 × 364 ×

    … × 344 × 343 365 × 365 × … × 365 × 365 = 0.492… 1 - 0.492… = 0.507… About 50%
  25. Heard Any of These? • “I’m terrible at Math” •

    “Math was always my worst subject” • “A million dollars, a billion, a trillion, whatever”
  26. Math Quiz: Girl’s Only! A woman is about to give

    birth to her first child. What are the odds that it’s a boy?
  27. Math Quiz: Girl’s Only! A woman is about to give

    birth to her first child. What are the odds that it’s a boy? ½
  28. Math Quiz: Round 2 A woman is about to give

    birth to her eighth child. The first seven were all boys. What are the odds that this child is a boy too?
  29. Math Quiz: Round 2 A woman is about to give

    birth to her eighth child. The first seven were all boys. What are the odds that this child is a boy too? ½
  30. Math Quiz: Round 3 You visit a friend, knowing she

    has two children but not the gender of the children. A young girl answers the door, so that’s one child. What are the odds that the other child is a boy?
  31. Math Quiz: Round 3 You visit a friend, knowing she

    has two children but not the gender of the children. A young girl answers the door, so that’s one child. What are the odds that the other child is a boy? ⅔
  32. Danica McKellar is on Our Side • Actress (Wendy on

    The Wonder Years) • Sex symbol • Math degree (with honors) • Published author • Chayes-McKellar-Winn theorem Image from http://allinone1-z.blogspot.com/2010/12/danica-mckellar-hotdanica-mckellar.html
  33. U.S. Math Literacy • The U.S. is below a 34

    country average • 17 of those 34 countries score better than we do while only 5 score below us (11 are roughly even with us) • Ranking math proficiency from level 1 to level 6, only 27% of U.S. students score 4 or higher 2009 statistics for 15-year-olds from http://nces.ed.gov/surveys/pisa/pisa2009highlights_3.asp
  34. A Biblical Flood • “…all the high mountains under the

    entire heavens were covered.”—Genesis 7:19 NIV • 10,000 to 20,000 feet of water • “And rain fell on the earth forty days and forty nights.”—Genesis 7:12 NIV • 960 hours of rainfall • That’s water rising about 15 feet per hour
  35. "The State Department is infested with communists. I have here

    in my hand a list of 205— a list of names that were made known to the Secretary of State as being members of the Communist Party and who nevertheless are still working and shaping policy in the State Department."—Joe McCarthy, U.S. Senator
  36. $100,000 Average $1 $1 $1 $1 $1 $1 $1 $1

    $1 $999.991 $100,000 $101,000 $98,500 $99,700 $103,200 $100,300 $99,000 $96,800 $100,000 $101,500
  37. Mean Verses Median $1 $1 $1 $1 $1 $1 $1

    $1 $1 $999.991 $100,000 $101,000 $98,500 $99,700 $103,200 $100,300 $99,000 $96,800 $100,000 $101,500
  38. Mean Verses Median $1 $1 $1 $1 $1 $1 $1

    $1 $1 $999.991 $100,000 $101,000 $98,500 $99,700 $103,200 $100,300 $99,000 $96,800 $100,000 $101,500 =$100,000 =$100,000
  39. Mean Verses Median $1 $1 $1 $1 $1 $1 $1

    $1 $1 $999.991 $100,000 $101,000 $98,500 $99,700 $103,200 $100,300 $99,000 $96,800 $100,000 $101,500 =$100,000 =$100,000 =$1 =$100,000
  40. Math Quiz Judy is thirty-three, unmarried, and quite assertive. A

    magna cum laude graduate, she majored in political science in college and was deeply involved in campus social affairs, especially in anti-discrimination and anti-nuclear issues. Which statement is more probable? (a) Judy works as a bank teller. (b) Judy works as a bank teller and is active in the feminist movement.
  41. Occam’s Razor (a) Judy works as a bank teller. (b)

    Judy works as a bank teller and is active in the feminist movement.
  42. Occam’s Razor (a) Judy works as a bank teller. (b)

    Judy works as a bank teller and is active in the feminist movement.
  43. Occam’s Razor (a) Judy works as a bank teller. (b)

    Judy works as a bank teller and is active in the feminist movement. Bank Teller Odds * Feminist Odds < Bank Teller Odds
  44. Polling • Any kind of polling is subject to statistical

    errors • This is where our margin of error comes from • Even that can (rarely) be off • You also have to worry about systemic errors
  45. Gerrymandering • Nick had to move to even try to

    get elected • That’s because politicians use packing and cracking to distribute votes • Nick’s district looks like a dinosaur • The Voting Rights Act made this illegal, but only when racial (political is fine)
  46. The Census • The constitution requires an “actual enumeration” of

    the population every 10 years • This process costs billions • It contains known systemic errors
  47. Is Sampling Legal? • In the past, the U.S. Census

    used both approaches • This has been fought out in the Supreme Court: • Sampling was declared unconstitutional • Imputation is still allowed
  48. It Takes More Than Just Math • Two gamblers wager

    $100 on coin flips • The first to win six flips takes the pot • Their game is interrupted when the score is five to three • How do we fairly divide the pot?
  49. Payout Arguments • Pay $100 to the gambler with five

    wins since he’s leading and the prize is all or nothing • Payout ⅝ and ⅜ of the pot for their respective wins • Pay ⅞ and ⅛ for the odds each man will win (½ × ½ × ½ = ⅛ and 1 - ⅛ = ⅞)
  50. Math Quiz You need to test the blood of 100

    patients for a disease. On average one in a 100 will have the disease. Can you find those that have the disease by doing less than 100 tests? (Givens: you have enough of each patient’s blood to test them several times and you can test multiple patients at once by combining samples.)
  51. Back to Front 3 4 1 3 × 2 1

    0 1 0 4 3 + 2 4 4
  52. Front to Back 3 4 1 3 × + 2

    4 4 3 0 0 0 9 0 4 1 2
  53. In Your Head 34 × 13 30 × 10 =

    300 30 × 3 = 90 + 300 = 390
  54. In Your Head 34 × 13 30 × 10 =

    300 30 × 3 = 90 + 300 = 390 4 × 10 = 40 + 390 = 430
  55. In Your Head 34 × 13 30 × 10 =

    300 30 × 3 = 90 + 300 = 390 4 × 10 = 40 + 390 = 430 4 × 3 = 12 + 430 = 442
  56. A Good Rule of Thumb • A lot of people

    choose to look up a new word when they first encounter it • It’s an equally good idea to look up new math when you encounter it • http://www.wolframalpha.com/ • Ask a math geek
  57. The Formulas P = L(i(1 + i)m) / ((1 +

    i)m - 1) B = L(1 + i)m - (1 + i)p) / ((1 + i)m - 1) P = Monthly payment L = Loan amout i = Monthly interest (6% loan: 0.06 / 12 = 0.005) m = Length of the loan in months B = Balance remaining p = Payments made