1.10 Sampling and data: using spreadsheets to view and summarize  (Page 4/6)

Another function that we will use to perform relative frequency and cumulative relative frequency is the absolute cell function . If I wanted to find the percentage of students who arrived on campus by car, I would need to take the sum of students who took the survey and drove a car then divide that number by the total number of students who took the survey. I would need to use the same process to find the relative frequency of students who took the bus, rode their bike, or walked to campus. Rather than enter that formula 4 times you will be able to copy and paste this formula from row to row if you use the absolute cell function. To create a cell that will never change even if you copy and paste a cell to a different column or row you will need to add a “$” dollar sign in front of the column and row signature. For instance if you want to keep cell h2 constant even if the formula is copied and pasted to a new row or column, you would need to write that cells name as $h$2, We will see an application of this as we work with relative frequency. When one copies a formula from one cell to another without the absolute cell function “$” the dollar sign, the formula is relative and the cell reference will change. Copy the cell that you used to enter =h2+h5 into a new row in the same column (if you entered it into K2, copy and paste it into cell K4. What happens? The value is not the same. Look at the formula bar and it will indicate that the new reference was +h4+h7. Why did that happen? The reference was relative and you kept the same column but moved down two rows the rows in the formula also changed by two. Now, put an absolute function sign “$” the dollar sign in front of the cell reference. Enter =$h$2+$h$5 in a cell. Then copy and paste this function to any other cell in a different row or column and you will see that the reference is absolute. It does not change.

Optional classroom exercise:

At your computer, try this exercise: (1) Download the file, Statistics First Day of Class Survey; (2) Save the file to your desktop and one other cloud or personal recording device (jump drive, email) Be sure to name this file as indicated above (name of project with your full name); (3) open the file in Google Spreadsheet and create sheet labels; (4) save file and open in Excel; (change at least one row or column by wrapping text, right justifying) (5) Clean the data file so that each column has only categorical information or measurement data with all the same units of measurement and any label (other than in the column headings) removed. (6) Enter a formula into a cell with a relative reference and then with an absolute reference. Copy and paste the two formulas into other columns or rows. What happens? (7) save the file again and post in the appropriate Moodle assignment.

Summarizing Data :

Categorical and measurement data are summarized differently as indicated in the text. Both categorical and measurement data can be summarized by frequency distributions but when we use charts and graphs to display data we will look at the difference between displaying categorical data using pie charts and bar graphs while we will use vertical or horizontal histograms, box plots, or stem and leaf graphs to display measurement data. In this chapter we will only address frequency distributions and the display of categorical data. In the next chapter you will learn how to display measurement data. For the following examples we will use data from the Statistics First Day of Class Survey using only sample data from How did you arrive on campus today? And The number of college credit hours you have completed to date.