The instructions below make use of the data file assignment1.csv which can be downloaded from the link (usually, by doing a right click on the link and choosing "save as" or "save link as").
This file is in CSV, or comma-separated value format. This limits the information that can be stored in terms of advanced spreadsheet features, but makes it entirely independent of the particular spreadsheet and version you are using.
The U.S. Environmental Protection Agency publishes data on fuel efficiency for cars sold in the U.S. As gasoline prices have risen, so has interest in conservation and fuel efficiency.
The data in assignment1.csv is an excerpt of the 2008 Model Year EPA data. We will use it to illustrate some aspects of sampling, and to get some experience using spreadsheets to draw samples.
There are approximately 2600 rows in the spreadsheet, each one corresponding to a make and model of car or truck.
Draw a simple random sample of 100 observations from the mpg column. You can use the sample function of the analysis toolpak (you may have to enable this tool package if it is not already there). Store the results in a column in the spreadsheet.
Repeat this nine times, storing the result in a different column each time.
Use the AVERAGE function to compute the average mpg for each sample.
What is the highest sample average among your 10 samples? What is the lowest?
Use the AVERAGE function to compute the average of all of the items in the original mpg column. How does this result compare to your sample averages?
Compute the AVERAGE of your sample AVERAGES. How does this number compare to the average of the original mpg column?