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Thursday, October 1, 2015

Thursday HW

Tonight, please complete questions b,c, and d on the "Normal Percentiles" worksheet provided in class (or below). Here are some hints/helpful info for your homework:

  • For each problem I need to see (1) a Normal model, shaded, (2) a z-score with work, and (3) normalcdf(____, _____).
  • Question (b) is like the SAT example we discussed in class--use those notes as a guide.
  • Question (c) is similar to our in-class example, but...
    • For (c), we're finding the % above; this means our z-score will represent the "lower bound," and we'll have to use +infinity (a really large #, 9999) as our upper bound
  • Question (d) asks you to find the % between two numbers
    • For this example, you will have to find 2 z-scores (find the z-score for 4, then for 6).
    • In this case, finding a % between, our z-scores represent the upper and lower bound
  • In terms of using your calculator, you can use these general formats:
    • % Below (Percentile) Questions:
      • normalcdf(-99999, z-score) OR 
      • For newer calculators: Lower = -9999, Upper = zscore, mu = 0, sigma = 1
    • % Above Questions:
      • normalcdf(zscore, 99999) OR
      • For newer calculators: Lower = zscore, Upper = 99999, mu = 0, sigma = 1
    • % Between questions
      • normalcdf(lower zscore, upper zscore)
  • You can also read through the yellow box (example 2) on page 112-113 for some calculator help
Tomorrow we'll continue to work with the Normal model! On Monday we'll finish our chapter 6 notes, and Tuesday we'll do some practice! Then, Wednesday = unit vocab test and Thursday = test day again!

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