Downloading, Manipulating and Displaying Data in …



URBDP 520 Quantitative Methods in Urban Design & Planning

Lab Session 1: Downloading, Manipulating, Analyzing and Displaying Data in SPSS

We will use ‘womenpower.txt’, a database of women executives.

1. Downloading Data

• First, download the database from the course webpage.

• Open the database in SPSS

o Do you need to change the ‘type of file’ in order to see the file and open it?

• Cases. Are there multiple lines for each case (each woman’s name)? Or, just 1 line per woman?

• Delimiters. What separates columns? Spaces, tabs, commas,…?

2. Manipulating Data

2a. Variable Properties.

• Notice at the bottom of the screen, there is a Data View and a Variable View. You can enter information about the variables in the Variable View sheet.

• Name. Are the given variable names useful for understanding what they represent? If not, change them! Try putting a space in one of the names, e.g. “Last Name”. Does SPSS allow you to have a space in the variable name? If not, abbreviate the name, and then provide a better description in the Label category.

• Type. The data can be a string, numeric, comma, dot, scientific notation, date, or custom currency. The most useful will be string (letters) and numeric (standard numbers). See the help file for definitions of other variable types.

• Decimals. You can set the number of decimal points for numeric data. Do you need a decimal point for the Age variable?

• Measure. The variable can be scale (intervals or ratios), nominal (for continuous data) or ordinal (numbers represent categories, for example, 1 = low, 2 = medium, 3 = high).

3. Analyzing & Displaying Data

3a. Age

• What is the range of ages of this group of women? Average age?

• Use Descriptive Statistics to display this.

o Go to Analyze->Descriptive Statistics->Descriptives

o Move the age variable in to the “Variable(s):” window.

o Click on Options to see which descriptive statistics are available. Does it make sense to get a sum?

• What would be the best way to see the distribution and frequency of ages graphically?

o Let’s try a histogram.

o Go to Graphs->Histogram and move the age variable in to the Variable window.

3b. Levels of Power

• Can we categorize the women’s positions in to Levels of Power? Can we represent this descriptive data (in words) in numbers?

o Let’s create 4 categories of power-level based on the position variable.

o We can do this 2 ways: 1) manually type-in a number for each of the 50 women, or 2) notice that there are some repetitive titles, e.g. CEO. Use the Calculate function to assign categories.

o Let’s try # 2.

o First, assign position titles a number from 1-4 on paper.

o Next, create a new column. Go to Data->Insert Variable.

• Assign variable properties to the Power variable using the Variable View sheet.

• Will our variable will be numeric, and we do not need decimals? Will this variable be nominal, ordinal, or scale data?

o Next, assign numbers to your Power column based on values in the Position column. We’ll use CEO as an example. I’d like to assign CEO a 1.

o Go to Transform->Compute

o In the Target Variable window, type the name of your variable, e.g. Power

o We’ll use a logical statement to calculate Power values.

o Click on the If button

o Move your Position variable in to the expression window and add ‘ = “CEO” ’. It should look like this: Position = “CEO”

o Click Continue.

o In the Numeric Expression window, enter 1, then click OK.

o Go ahead and do this for the rest of the position titles.

• What percentage of these women fall within your 4 power-levels?

o Let’s look at both percentages and graphic.

o Analyze->Descriptives->Frequencies

o Move the power variable over to the Variable(s): window and click OK.

o Also, take a look at a histogram of this variable.

3c. Exporting Graphics

• You may want to export or use output graphics in your assignments or reports. Let’s try to bring the last power-histogram in to a Word document. The histogram should have a title, the axes should be labeled, and you should explain what the graph is showing.

• Take a look at your histogram. Does it have a title? If not, you may want to re-do the graph. When you get the Histogram window (Graphs->Histogram), there is a “Titles…” button in the lower right hand corner.

• There are 2 options for bringing SPSS output graphics in to Word: 1) copy and paste, or 2) exporting. Exporting allows you more flexibility – for charts you can adjust the color and file size. For numeric output, such as your Descriptive Statistics table, you can export the table as an image, or as text (so that you can edit it once it’s in Word). Try experimenting with both methods.

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