Day 18: Statistics for Business Applications

Last Time: Examples using the t-distribution
- Major issue: sample standard deviation (s), rather than population value (sigma).
- Major twist: degrees of freedom is now required.
- Assure that the use of t is appropriate
Notes:
- Recall that we have a test coming up Tuesday.
- Chapter 12 homework (over Section 12.1 and 12.2) will also be due on Tuesday.
Today:
- Review for test 2 - sections 9.1-9.3, 10.1-10.4, 11.1-3
  - Extracts from objectives
  - Vocabulary (including at least the following):
    - Standard error of the mean (the standard deviation of xbar)
    - point and interval estimators
    - unbiased estimator
    - consistent estimator
    - relative efficiency
    - null and alternative hypotheses
    - p-value
    - rejection region
  - comments on homework (thanks to Carl Miller)
    - Set A
    - Set B
- A bit more on the t-distribution problems (Sections 12.1-2)
  - #12.32 (test of hypothesis, using Minitab: Stat -> Basic Statistics -> 1-sample t)
    Compare versus a mu of 18 as well (use table).
  - #12.44 (constructing a confidence interval; by hand, and using Minitab)
- Proportions p and associated C.I.s (Section 12.4)
  - Test statistic for p (recall from 9.3)
  - Confidence interval estimator of p (when p is unknown!)
    - Nielson example (recode, using Manip->code->numeric to numeric: 1 -> 1, 2:5 -> 0)
  - Sample size calculations for p
Next time: Test 2

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