Day 21: Statistics for Business Applications

Last Time: Test 2
- Confidence interval estimator of p (when p is unknown!)
  - We can try to use p hat (the estimate of p)
  - Conservative standard error: use p=.5
  - Nielson example (recode, using Manip->code->numeric to numeric: 1 -> 1, 2:5 -> 0)
- Sample size calculations for p
Sorry, I don't have the test graded yet.
Return problems 12.1-12.2
- 12.46, p. 366
Questions about CI and proportions?
Homework for section 12.4 due next time
You may do the Review problems (p. 387-388) as a replacement homework, if you wish.
Today: Difference between two sample means (independent samples)
- Today, we'll worry only about the case of equal variances. Here's the theory....
- 13.39, p. 410 (Example handout, assuming equal variances)
- Type of problem: heights and travel distances of NKU students -- males versus females.
Next time: Finish sections 13.1-2 - inference about the difference of two means

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