Day 09: Statistics for Business Applications

Last Time: Began Section 9.1-9.2:
- The larger the sample size, the closer to the true mean is the sample mean (hence, the smaller the spread of the distribution of sample means).
- The central limit theorem
Today:
- Important Notes:
  - Our first test is Thursday! It will cover only through chapter 8 - nothing from 9 will appear.
  - You should review the Objectives for those four chapters that will appear.
  - formula sheet
  - A normal probability table will be provided.
  - Chapter 8 homework solutions
  - Last year's test
  - Problems from Section 9.1-9.2 will be due next Thursday, 2/19
  - Problems from Section 9.3 will be due the following Tuesday, 2/24
  - On conventions: apologies for using the "lefthand" version of Z_A.
- More from 9.2:
  - Applets for section 9.2 - even skewed distributions can give rise to normally distributed sample means (the larger the sample size, the less skew).
  - Some examples
- Section 9.3 - sampling distribution of a proportion
  - We're talking about variables that can be classified into two cases: success and failure.
    
    Note:
    success is not always a good thing!
    Example: males and females who answered our survey for stats classes this term (Excel).
  - The sampling distribution of a proportion
  - Some examples
Next time: Test 1!

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