Descriptions of Quantitative Data Continued

1. 1
Chapter 11: Descriptions of
Quantitative Data Continued

2. Graphics and Narratives
 Developing Graphics
 Interval and Ratio
 Histograms and line graphs
 Nominal and Ordinal
 Pie charts or bar charts
 Writing the Narrative
 If objective of the research is to compare 2 or
more groups, provide only the descriptive
information for each group
2

3. Bar Chart
 Used to compare things between different
groups
 Or track changes over time
 Useful for data that’s easy to categorize
3

4. Line Chart
 Used when you want to show a trend in
data at equal intervals
 E.g.
 Change in student enrollment over the school
year
 Number of travelers on two different airlines
for each quarter
4

5. Pie Chart
 Used when you want to show the
proportion of an item that makes up a
series of data points
 E.g.
 Percentage of children living in poverty by
ethnicity
 Proportion of night students and day students
enrolled
 Age of participants by gender
5

6. Pivot Tables
 Allows you to summarize information that
you find in lists and tables without using
any formulas or functions
 Be able to take already created data and
create tables that extract exactly the
information you want to use
6

7. 7
Frequency Tables
 Summarize descriptive data
GPA range* n Percent
1.5-1.99 3 1.6
2.0 – 2.49 7 3.7
2.5 – 2.99 10 5.3
3.0 – 3.49 124 65.3
3.5 – 4.0 46 24.2
TOTAL N = 190 100.0
Table 1: GPA of Black Feather Youth
= 3.21; STD = .41; Median = 3.2; Mode = 3.0
Min. = 1.5; Max. = 4.0; Range =2.5
X

8. 8
Using Graphs to Display Data
 Trend graph / Pie Chart
Mean Attitude Towards Police by Age
0
5
10
15
20
25
30
Age
Score
10 15 20 25 30
Line graph illustrating Attitude Towards Police by Age
52.6%
47.4%
Female
Male
Pie chart illustrating the proportion of males
and females responding to the Black Feather
Youth Survey (N = 190)

9. Writing the Narrative
 Always address data contained in tables, but avoid
discussing every detail
 Tables and graphics should be placed near the
location in the narrative where they are mentioned
 Interval and ratio data should be described with
means, standard deviations and Ns
 Median, minimum, and maximum if not normal distribution
 Always report Ns when reporting percentages
 Only use percentages to compare groups that are
similar in size, otherwise misleading
 Avoid reporting percentages for small group
 50% is less than 10 cases 9