Distance Education Statistics
Lab B
Eric Parslow
and
Russell T. Hurlburt
University of Nevada, Las Vegas
This lab will consist of 6 parts:
Exploring ESTAT's 'meanest' exercise.
Exploring ESTAT's 'meannum' exercise.
Exploring ESTAT's 'sdest' exercise.
Exploring ESTAT's 'sdnum' exercise.
Continuing to explore ESTAT's 'datagen' computational program.
The quiz
Part I - Exploring ESTAT's 'meanest'
1. Open ESTAT and click on the button labeled "meanest" (in the upper-left) to launch the meanest exercise.
2. Take the "Tutorial" by clicking the "Tutorial" button to get specific instructions.
3. Your task is to 'drag' the arrow at the bottom of the histogram to the eyeball estimated mean. Use the "Help" button for assistance.
4. Practice eyeball estimating the mean until your "eyeball error" is consistently less than 3%. Do at least six or eight new data sets.
5. Macintosh users: the "contents" button will return you to ESTAT's main menu.
Part II - Exploring ESTAT's 'meannum'
1. Click on the button labeled "meannum" to launch the meannum exercise.
2. Take the "Tutorial" by clicking the "Tutorial" button to get specific instructions.
3. Using the 'range method', eyeball estimate the mean of the given data sets. Don't forget the "Help" buttons for more specific instruction.
4. Practice this until your "eyeball error" is consistently less than 10%. Do at least six or eight new data sets.
5. Macintosh users: use "Contents" to return to the main menu.
Part III - Exploring ESTAT's 'sdest'
1. Click on the button labeled "sdest" to launch.
2. Take the "Tutorial" by clicking the "Tutorial" button to get specific instructions. The "Tutorial" may be particularly helpful in this exercise.
3. Practice eyeball estimating the mean and standard deviation of histograms.. The "Help" button may be very useful.
4. Both of your eyeball errors should be consistently below 3%. Do at least six or eight new data sets.
5. Macintosh users: use "Contents" to return to the main menu.
Part IV - Exploring ESTAT's 'sdnum'
1. Click on "sdnum" to launch the exercise.
2. Take the "Tutorial" by clicking the "Tutorial" button to get specific instructions.
3. Using the 'range method', eyeball estimate the standard deviations of the data set. The "Help" buttons may be particularly useful.
4. Do not focus too much on the Conversion Factor table. You should gain a "feel" for what number to divide by (i.e. you shouldn't have to count how many pieces of data are given - small tables use 3, medium use 4, large use 5, etc...).
5. Practice this until your "eyeball error" is consistently less than 10%. Do at least six or eight new data sets.
6. Macintosh users: use "Contents" to return to the main menu.
Part V - Continuing to explore ESTAT's 'datagen' computational program
1. Open datagen.
2. The object of this portion of the lab is to observe and understand the effect of changing data on the various calculations we perform.
3. Create a data set with five points as follows: Highlight the first five cells in the first column of the datagen spreadsheet; click the "Generate" button; click OK.
3A: Duplicate that data set into the second column as follows: Highlight the first five cells in the first column (as before); click Ctrl-C (or click Edit > Copy)to copy those points to the clipboard; click the first cell in the second column; click Ctrl-V (or click Edit > Paste)to paste those values into the second column. Now you should have two identical columns.
4. Notice that the means and standard deviations of both columns are automatically displayed in the datagen Descrpitive Statistics window. Now play around with the values in the first column of the spreadsheet and figure out how to change the standard deviation without changing the mean. (Note that the original mean and standard deviation will continue to be displayed in the second column.)
5. Solution to step 4: By choosing points on either side of the mean and moving both data points equal amounts towards or away from the mean, the standard deviation will change while the mean will stay the same.
6. Accomplish, practice, and contemplate this, using different sets of data.
7. Using a new data set, attempt to change the mean without changing the standard deviation. Use 5 data points.
8. Solution to step 7: If you move ALL the data points one direction or another by an equal amount, the mean will change but the standard deviation will remain the same.
9. This can be easily done using the "Edit Variable" and "Add Value to Every Point" functions. Note that if you add a negative value, it is identical to subtracting.
10. Accomplish, practice, and contemplate.
11. Return to the main menu and review any of these exercises which you found difficult.
Part VI - The Quiz
When you have mastered Parts 1-5, click Take the Lab Quiz below.
You will need the quiz password, which is
7654321
