1 / 12

3.2 Measures of Variability

3.2 Measures of Variability. Objectives: By the end of this section, I will be able to… Understand and calculate the range of a data set. Explain in my own words what a deviation is. Calculate the variance and the standard deviation for a population or a sample. What is variation ? .

takara
Download Presentation

3.2 Measures of Variability

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. 3.2 Measures of Variability Objectives: By the end of this section, I will be able to… • Understand and calculate the range of a data set. • Explain in my own words what a deviation is. • Calculate the variance and the standard deviation for a population or a sample.

  2. What is variation? It is the spread of the numbers around the mean.

  3. Measures of Variation • Variance • Standard Deviation • Range Highest – Lowest

  4. Why is VARIATION important? Because less variation means smaller spread in the data, which means • More precise estimates • Higher confidence in our conclusions about the data

  5. Wall Street Journal competition • Stocks were chosen by • Journal staff randomly throwing darts at a list of the stocks • A team of four financial experts • The DJIA (Dow Jones Industrial Average)

  6. THE RESULTS ARE…

  7. Variations and Graphs

  8. Measuring V-Span 1. Make a V between your index finger and your middle finger when you spread them as far as possible. 2. Measure to the nearest tenth of a centimeter. Your V-Span = 3. Compute the group’s mean V-Span. Mean V-Span = 4. Now fill out the following chart with your data and find the three values of variation

  9. Then use the mean (average V-span) and find the difference between each x value and the mean Square the number you just found… Put in all of your V-spans as x values. Add rows as necessary. Variance = Sum/(n – 1) Standard deviation = Square ROOT of the variance

  10. Calculator Time • Find the variance and standard deviation on your calculator.

  11. NASCAR TIME - link • On a separate sheet of paper, and one per person – NEATLY complete the following. • Find the mean, median, mode, range, variance, and standard deviation of NASCAR points of the top 10 drivers for 2010.

More Related