Day 03: Statistics for Business Applications

You should be able to interpret a histogram:

• Describe the shape:
  • symmetric
  • positively skewed
  • negatitively skewed
  • unimodal
  • bimodal
• What are typical (central) values?
• What are the largest and smallest values?
• Are there unusual or atypical values?

1. Example: heights of NKU students
2. Example from the 212 website (here's the data as a text file, in case you'd like to try it yourself)
3. Example using Minitab and baseball data from chapter 4
4. Example using Minitab and Telephone Bill data from chapter 2

• mean

  • Also known as the arithmetic average
  • Notation:
    • population ("mu") versus sample means ("xbar")
    • sigma notation
  • Sensitive to unusual, extreme values

• median

  • the middle value: insensitive to unusual, extreme values; but not as good as the mean for purposes of statistical inference.
  • In the event that there are an even number of data values, the median is the mean of the two values "in the middle".

• mode

  the most popular value (or midpoint of the class with largest frequency)