Drexel University
College of Information Science and Technology
Course: Action Research
Assignment Two: Descriptive Statistics
Instructor: Glenn Booker
Name: ______________
Date: ___________
These are scores on an exam taken by 40 employees in your organization.
63
68
77
94
88
76
75
79
79
46
98
52
92
81
81
82
86
92
82
77
87
77
81
81
83
84
87
77
78
76
78
70
40
70
70
74
67
66
60
61
Using these data, do the following without SPSS. Show your work!
You may use plain arithmetic (+ - / *) in Excel to help do the calculations.
1.
Create a frequency distribution table; include columns for cumulative frequency
and cumulative percent. Scores should be listed in ascending order (smallest to
highest).
Score Frequency Cum. Freq. Cum. Percent
etc.
2.
Find the mean, median, and mode(s).
3.
Find the variance and the standard deviation.
4.
Using the mean and standard deviation just calculated, find the Z score for the
employee who scored 84 on the exam.
a. According to your Z-score table (PDF page 38 of Action Research handout),
what percentage of the class scored above the employee who scored 84?
b. What percentage scored below her? Remember that the answers for 4a and 4b
should total 100%!
c. On a second test, this employee received a score of 91. The class mean was 82
and the standard deviation was 11. Use Z scores to determine on which test, the
first or the second, the employee performed better relative to the class.
5. Now use SPSS to check your computations of mean, median, mode, standard
deviation, and Z score. You will need to enter the 40 information technology exam
scores above into the SPSS Data Editor to do so. You can use the SPSS Tutorial
(under Help), “Using the Data Editor” for help with data entry.
Drexel University
College of Information Science and Technology
a.
b.
Use Analyze > Descriptive Statistics > Frequencies to generate a frequency
distribution of scores and the relevant summary statistics. Show your results.
Were your hand-computed figures correct?
Run Analyze > Descriptive Statistics > Descriptives with "Save standardized
values as variables,” which will convert the 40 scores to Z scores in a new
column. Was your calculation of the Z score for the raw score of 84 correct?
(The new variable will have Z in front of the existing variable’s name. You do
not need to show the spreadsheet.)