![Page 1: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/1.jpg)
Data analysis: frequencies
GAP Toolkit 5 Training in basic drug abuse data management and analysis
Training session 8
![Page 2: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/2.jpg)
Objectives
• Introduce univariate, descriptive statistics as the first step in a process of data analysis, starting from exploration and moving towards more sophisticated techniques
• Distinguish between frequencies and relative frequencies
• Introduce frequency and probability distributions as data models
![Page 3: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/3.jpg)
Descriptive Statistics
• Univariate• Categorical data• Continuous data
![Page 4: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/4.jpg)
SPSS Descriptive Statistics
• Analyse/Descriptive Statistics/Frequencies• Analyse/Descriptive Statistics/Explore• Analyse/Descriptive Statistics/Descriptives
![Page 5: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/5.jpg)
Frequency vs relative frequency
• “The frequency of any value of a variable is the number of times that value occurs in the data; that is, a frequency is a count. The relative frequency of any value is the proportion or fraction or percent of all observations that have that value.”
(D. S. Moore, Statistics: Concepts and Controversies, 5th ed. (New York, W. H. Freeman Press, 2000)).
![Page 6: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/6.jpg)
Frequency distribution/probability distribution
• Frequency distribution: all possible values of the variable and their associated counts
• Probability distribution: all possible values of the variable and their associated probabilities (relative frequencies)
![Page 7: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/7.jpg)
Percentages
• Let: – f1 = the number of cases in category 1– n = the total number of cases
• The percentage of cases in category 1:
%100*1 n
f
![Page 8: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/8.jpg)
Exercise: frequency of referral
• Construct a frequency table for referral source in the file main.sav
![Page 9: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/9.jpg)
Frequency Percent Valid Percent Cumulative Percent
Valid Self/Fam/Friends 586 37.3 38.0 38.0
Employer 195 12.4 12.7 50.7
Health Pro 194 12.3 12.6 63.3
Religious Grp 65 4.1 4.2 67.5
Hosp/Clinic 53 3.4 3.4 70.9
Welfare 252 16.0 16.4 87.3
Courts/Corrections 100 6.4 6.5 93.8
School 64 4.1 4.2 97.9
Unknown 32 2.0 2.1 100.0
Total 1541 98.1 100.0
Missing System 30 1.9
Total 1571 100.0
Referral
![Page 10: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/10.jpg)
Frequencies: Format button
![Page 11: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/11.jpg)
Frequency Percent Valid Percent Cumulative Percent
Valid Self/fam/friends 586 37.3 38.0 38.0
Welfare 252 16.0 16.4 54.4
Employer 195 12.4 12.7 67.0
Health pro 194 12.3 12.6 79.6
Courts/corrections 100 6.4 6.5 86.1
Religious grp 65 4.1 4.2 90.3
School 64 4.1 4.2 94.5
Hosp/clinic 53 3.4 3.4 97.9
Unknown 32 2.0 2.1 100.0
Total 1541 98.1 100.0
Missing System 30 1.9
Total 1571 100.0
Referral
![Page 12: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/12.jpg)
Frequencies: Charts button
![Page 13: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/13.jpg)
Referral
Referral
Unknown
Hosp/Clinic
School
Relgious Grp
Courts/Corrections
Health Pro
Employer
Welfare
Self/Fam/Friends
Pe
rce
nt
50
40
30
20
10
0
![Page 14: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/14.jpg)
Frequencies: Statistics button
![Page 15: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/15.jpg)
Referral
N Valid 1541
Missing 30
Mode 1
Statistics
![Page 16: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/16.jpg)
Frequencies: syntax
• FREQUENCIES• VARIABLES=refsourc• /FORMAT=DFREQ• /STATISTICS=MODE• /BARCHART PERCENT• /ORDER=ANALYSIS.
![Page 17: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/17.jpg)
Exercise: frequencies
• Generate a frequency table and bar chart for each of the following variables and comment:– Race– Education– Employment
• Save the output and the syntax file
![Page 18: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/18.jpg)
Frequency: Race
Frequency Percent Valid Percent Cumulative Percent
Valid Coloured 722 46.0 52.8 52.8
White 520 33.1 38.0 90.8
African 109 6.9 8.0 98.8
Asian 17 1.1 1.2 100.0
Total 1368 87.1 100.0
Missing System 203 12.9
Total 1571 100.0
Race
![Page 19: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/19.jpg)
Frequency: Education
Frequency Percent Valid Percent Cumulative Percent
Valid Secondary 978 62.3 64.3 64.3
Primary 332 21.1 21.8 86.2
Tertiary 189 12.0 12.4 98.6
None/pre-primary 21 1.3 1.4 100.0
Total 1520 96.8 100.0
Missing System 51 3.2
Total 1571 100.0
Education
![Page 20: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/20.jpg)
Frequency: Employment
Frequency Percent Valid Percent Cumulative Percent
Valid Working full-time 571 36.3 36.6 36.6
Not working 569 36.2 36.4 73.0
Student/pupil 240 15.3 15.4 88.3
Working part-time 68 4.3 4.4 92.7
Pensioner 34 2.2 2.2 94.9
Disabled 33 2.1 2.1 97.0
Housewife 28 1.8 1.8 98.8
Other 18 1.1 1.2 99.9
Apprentice 1 .1 .1 100.0
Total 1562 99.4 100.0
Missing System 9 .6
Total 1571 100.0
Employment
![Page 21: Data analysis: frequencies GAP Toolkit 5 Training in basic drug abuse data management and analysis Training session 8](https://reader036.vdocuments.us/reader036/viewer/2022062312/551a0bf355034619378b4cac/html5/thumbnails/21.jpg)
Summary
• Frequencies and relative frequencies• Frequency distributions and probability distributions• Format/ordering• Bar charts• Statistics/mode