PSY 231, SPSS Manual, Frequency Dist./Central Tendency
6
Name ____________________
Section ____________________
Date ____________________
Frequency Distributions/Measures of Central Tendency
Read the chapter in your text that corresponds to frequency distributions
and measures of central tendency and define the following terms:
¾ Descriptive Statistics _________________________________________
__________________________________________________________
¾ Regular Frequency Distribution ___________________________________
__________________________________________________________
¾ Cumulative Frequency Distribution _________________________________
___________________________________________________________
¾ Real Limits __________________________________________________
¾ Apparent Limits ______________________________________________
¾ Histogram __________________________________________________
¾ Bar Graph __________________________________________________
¾ Frequency Polygon _____________________________________________
¾ Skewed Distribution ___________________________________________
¾ Symmetrical Distribution _______________________________________
¾ Relative Frequency ____________________________________________
¾ Class Interval ________________________________________________
¾ Mean ______________________________________________________
¾ Mode ______________________________________________________
¾ Median _____________________________________________________
Computer Exercise: Frequency Distributions using SPSS
The following data are the results of the first Introduction to Statistics exam
(100 points possible).
76, 75, 80, 90, 58, 45, 89, 86, 87, 88, 78, 90, 93, 92, 86, 83, 76, 91, 80, 81, 81, 78,
86, 75, 82, 98, 78, 91, 90, 92, 76, 68, 63, 64, 89, 98, 100, 65, 85, 90
¾ Open the SPSS Data Editor and enter data into the columns. (Refer to “Data
Input and the SPSS Screen” for the procedure for opening SPSS and entering
data.) Use two columns headed by the variables “Student” and “Score.” Use the
Copyright © 2000 Elizabeth Jacobs
PSY 231, SPSS Manual, Frequency Dist./Central Tendency
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Student column to assign a student/subject number to each score. For the
first score, a “1” is entered under “Student” and then a “76” is entered in the
“Score” column.
¾ Click on “Analyze” --> “Descriptive Statistics” and then click on “Frequencies.” A
dialog box will appear that lists the variables from the data editor, in this case,
“Student” and “Score.”
¾ Click on “Score” and then the right arrow between the windows to indicate that
we want the analysis done only on the variable “Score.” (Since “Student” is a
nominal variable it will not be analyzed.)
¾ Click on the “Statistics” button on the bottom of the screen to get to the
statistics dialog box.
¾ Under “Central Tendency” select Mean, Median, and Mode.
¾ Click on “Continue” to return to the “Frequencies” dialog box.
¾ Click on “Format” at the bottom of the “Frequencies” dialog box and click in the
circle in front of “Descending Values.” Click on “Continue” to return to the
“Frequencies” dialog box and then on “OK” to begin the analysis.
Reading the Tables:
The Statistics Table lists N, and the variables that were selected in the
“Statistics” menu. The Statistics Table also indicates if any data are missing from
the data editor which may happen in cases where there are several variables for
each subject and some of the data are missing, e.g., a student answered every
question except GPA.
The Frequency Table lists all scores entered into the Data Editor, the frequency
of each, the relative percentage of each (f/N), and the cumulative percentage of
each. This table also has a column labeled “Valid Percent” takes missing data into
account as the relative percentage is calculated.
¾ Double-click on the heading “Frequencies” at the top of the output page and
label the data “Statistics Exam, [today’s date].”
Copyright © 2000 Elizabeth Jacobs
PSY 231, SPSS Manual, Frequency Dist./Central Tendency
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¾ Answer the following questions:
What is the Mean of this distribution?
What is the Mode?
What is the Median?
___________
___________
___________
¾ What score represents the 50th percentile?
___________
¾ What proportion of the students scored above 70%
___________
¾ What proportion of the student scored below 60%
___________
¾ In general, how would you describe the results of this test?
______________________________________________________
______________________________________________________
______________________________________________________
¾ What roles do the teacher, students, and the test itself, play in how well or
poorly the students did on this test?
_______________________________________________________
_______________________________________________________
_______________________________________________________
¾ Turn in this sheet along with a copy of your Data Editor and Output pages.
Copyright © 2000 Elizabeth Jacobs