PSY 200 Experimental Methods: Lab 2 Practice with Descriptive Statistics in SPSS
1. Read and practice all of the following descriptive statistics. On a later date, we will have a lab practical that tests each of your abilities (individually) to carry out these analyses efficiently within a limited amount of time. Therefore, the practice problems provided should help you assess your abilities to move from the textbook description to a novel problem.
2. Read and carry out all procedures described in Chapter 3 of Cronk’s book a. Frequency distributions and percentile ranks for a single variable a.i. Creating a frequency distribution: (Use the CAR_SALES.sav data file that comes with SPSS. See instructions to find it.) a.ii. Determining percentile ranks a.iii. Practice exercise: Using Practice Data Set 1 in the course website, create a frequency distribution table for the mathematics skills scores. Determine the mathematics skills score at which the 60th percentile lies. Write the answer here: ______
b. Frequency distributions and percentile ranks for multiple variables b.i. Read carefully and carry out the analyses described in: Using Crosstabs; Interpreting crosstabs output. b.ii. Practice exercise: Using Practice Data Set 1 in the course website, create a contingency table using the Crosstabs command. Determine the number of participants in each combination of the variables SEX and MARITAL. What percentage of participants is married? ______. What percentage of participants is male and married? ______.
c. Measures of central tendency and measures of dispersion for a single group c.i. Read carefully and carry out the analyses described in: Focus on Assumptions (it reviews their meanings); Running the command; Reading the output. c.ii. Practice exercise: Using Practice Data Set 1 in the course website, obtain the descriptive statistics for the age of the participants. What is the mean? _____. The median? ______. The mode? ______. What is the standard deviation? ______. The Minimum? ______The Maximum? ______. The range? ______.
d. Measures of central tendency and measures of dispersion for multiple groups. d.i. Read carefully and carry out the analyses described in: Description, Assumptions, Drawing Conclusions, SPSS Data Format, Running the command, Reading the output d.ii. Extension to more than one independent variable d.iii. Practice exercise: Using Practice Data Set 1 in the course website, compute the mean and standard deviation of ages for each value of marital status. What is the average age of the married participants? ______. The single participants? ______. The divorced participants? ______. e. Standard scores e.i. Read carefully and carry out the analyses described in: Description, Assumptions, Drawing Conclusions, SPSS Data Format, Running the Command, Reading the Output. The data file (Sample.sav is available on the course website. e.ii. Practice Exercise: Using Practice Data Set 2 in the course website, determine the z-score that corresponds to each employee’s salary. Determine the mean z-score for salaries of male: ______and female employees: ______. Determine the mean z-score for salaries of the total sample: ______.
f. All done with this chapter!
3. Now let’s learn more about descriptive statistics in SPSS from Chapter 6 of SPSS Survival Manual, provided on the course website. You should download and open the SPSS data file called Survey3ED.sav from the course website. Please carry out the instructions in SPSS as you read and follow along with the text. Please read carefully to learn about these descriptive statistics, not just how to run SPSS. a. Categorical variables; interpretation of output from frequencies b. Continuous variables; interpretation of output from descriptives c. Missing Data!!!!! What should you do? What are your options? d. Assessing Normality (what is the purpose?); Procedure for assessing normality using Explore; interpretation of output from Explore e. Carefully examine and understand all four figures. f. Checking for outliers (Why is this necessary?). HOW do you check for them? Write your answer here:
4. Additional practice exercises: a. Business: follow the instructions using the data file Staffsurvey5ED.sav on the course website. Answer each question below. b. Health: follow the instructions using the data file Sleep5ED.sav on the course website. Answer each question in the space below.
5. Finishing up: a. No need to keep any of the files. b. Shut down the computer (don’t just close the cover or press the “OFF” button!)