1 / 8

Elementary Applied Statistics

Elementary Applied Statistics. Kathy Ensor, Chair Department of Statistics. What is Statistics?. “Statistics is the science of collecting, organizing, and interpreting numerical facts, which we call data”. Pg xxv

longnecker
Download Presentation

Elementary Applied Statistics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Elementary Applied Statistics Kathy Ensor, Chair Department of Statistics

  2. What is Statistics? • “Statistics is the science of collecting, organizing, and interpreting numerical facts, which we call data”. Pg xxv • Based on a “representative sample” what can we say about the population of interest? • Use of statistics is pervasive in our society. • Examples?

  3. Data? • Numerical facts? • Numerical summaries of what? • Sampling unit - the object or individual on which we are taking a measurement • Sampling frame or population - the group from which the sampling units are selected • Variable - the characteristic of the sampling unit that we measure

  4. Categorical Variable • The sampling unit belongs to one of several groups. • Examples? - time for you to speak up! • Nominal - No ordering to the categories (blue, red, green, yellow) • Ordinal - there is a natural ordering to the categories (excellent, very good, good, …)

  5. Quantitative variable • Numerical measures of a variable • Examples? • Arithmetic operations make sense (adding, dividing…) • Ratio and interval scales

  6. Distribution • A variable can take on a range of values. • The values do not occur in equal numbers • “The distribution of a variable tells us what values it takes and how often it takes these values.” • Variables exhibit variation; the distribution is the pattern of this variation

  7. Displaying Distributions with Graphs • Categorical data • Pie charts • Bar charts • A plot of the count for each category of the variable. • What information can you glean from these graphs? Which is the better of the two?

  8. Quantitative Variables • Stemplots (stem and leaf plot) • Back to back stem and leaf plot • describing two variables. • Histogram • frequency or relative frequency of the number of values of the variable falling into the specified interval.

More Related