Day 27: Statistics for Business Applications

• Last Time: Testing the difference in two proportions (especially M&Ms!)

• Test Thursday: sections 12.1,2,4; 13.1,2,4

• Homework 13.6 due Thursday

• Return 13.4 homework

• Today:
  • (Brief) review for the test:
    • Last year's Test 3 and key
    • From the objectives
    • Formulas
    • Why t-tests?
    • Reading t-tables
    • Proportions stick with z-tests.
    • Finding confidence intervals and testing hypotheses
    • Interpreting Minitab output
    • Don't forget about old stuff!

  • More on linear regression: "...to predict the value of one variable on the basis of other variables."
    • Fahrenheit/Celsius conversion
      • local temperatures

    • How does linear regression work?
      • Do scatter plots indicate a linear (i.e. straight line) relationship?
      • "Correlation" measures a linear relationship.
      • How do we find a "best-fit" line?
      • How good is that line?

    • "How to" from our handy statistics guide pages.... (here's the data)

    • How well does homework predict test grade?

    • Which Honda Odyssey to buy?

    • Example: 18.8, p. 614

• Next time: Test 3

Links:

• A nice on-line course about regression