Other's On-Line Resources (Chapter 2)

 

Fun With Histograms
  • Description:
    Using this interactive on-line resource, you can play with a histogram--building it any way you wish--and immediately see the impact of your actions on your data set's mean, median, SD, and skewness.

  • What to Do:
    1. Click on the colored title of this on-line resource: "Fun With Histograms."
    2. After the next screen pops up, click on the "Begin" button that's located under the heading "Mean and Median."
    3. On the new screen that pops up, you'll see a blue histogram and (to the left of the histogram) a set of descriptive statistics for the histogram's data. By clicking above or below any of the building blocks that create a vertical column in the blue histogram, you can make that particular column taller or shorter.
    4. As you make changes to the histogram's shape, note the changes in the desriptive statistics: N, the mean and median, the standard deviation, and skewness.

  • Sky Huck's Puzzle Question:
    With N equal to 15, it's possible to build a histogram such that (a) the range extends from 1-9, (b) no frequency = 0, (c) the mean and median are each exactly twice as large as the standard deviation, and (d) skewness = 0. Can you accomplish this feat?
     
More Fun With Histograms
  • Description:
    This interactive on-line resource allows you to change the width of the columns in a histogram and thereby see that the true distributional shape of data can be MISREPRESENTED if the column width is not selected properly.

  • What to Do:
    1. Click on the colored title of this on-line resource: "More Fun With Histograms."
    2. After the next screen pops up, read the initial paragraph of text.
    3. Move the black triangle (under the horizontal "bin width" bar) to change the width of the columns in the histogram, noting how the histogram's shape changes.

  • Sky Huck's Puzzle Question:
    Was the mean eruption duration closer to the shortest eruption or the longest eruption?
     
How's Your Reaction Time?
  • Description:
    In this interactive resource, you first generate data by performing a simple reaction-time task. Then, you get to see how you did, with your data summarized by means of box plots, histograms, means, medians, the upper and lower quartile points, the SD, and indices of skewness and kurtosis.

  • What to Do:
    1. Click on the colored title of this on-line resource: "How's Your Reaction Time."
    2. After the next screen pops up, click on the "Begin" button that's located under the heading "Comparing Distributions."
    3. On the new screen that pops up, read the instructions carefully and then click on the "Begin" button.
    4. Continue clicking on the small and large squares until you see a summary of your reaction time data.

  • Sky Huck's Puzzle Question:
    Try to perform the reaction-time task such that your scores for the small squares are positively skewed whereas your scores for the large squares are negatively skewed.
     
Stem-and-Leaf Displays
  • Description:
    You'll see a stem-and-leaf display for a real study involving 147 people who had their arm strength measured.

  • What to Do:
    1. Click on the colored title of this on-line resource: "Stem-and-Leaf Displays."
    2. After the next screen pops up, read the short paragraph under the heading "ARM" and then scroll down to examine (1) descriptive statistics for the amount of force exerted by the 147 folks who were studied and (2) a stem-and-leaf display showing each of the 147 scores.
    3. Be sure to click on the colored term "stem-and-leaf"; this will give you a two-page explanation of how stem-and-leaf displays are constructed.

  • Sky Huck's Question to You:
    Can you correctly answer, on your first try, the multiple-choice question that appears immediately below the stem-and-leaf display?
     

Copyright © 2012

Schuyler W. Huck
All rights reserved.

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