# Fundamentals of Engineering - PowerPoint PPT Presentation

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## Fundamentals of Engineering

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### Fundamentals of Engineering Graphing as a Communication Tool GSMST AU 2006 * Objectives: * Objectives: At the end of the session, students should be able to ... – PowerPoint PPT presentation

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Title: Fundamentals of Engineering

1
Fundamentals of Engineering
• Graphing as a Communication Tool
• GSMST

2
Graphing as a Communication Tool
• It's been said that a picture is worth
• a thousand words
• but when displaying data, what kind of picture
(graph, chart) should you use? How do you make
your graph best show what you want?

3
Objectives
• Introduce basic chart types
• Basic equation types
• Good graphing practices
• Chart examples

4
Which Type of Graph?
• What kind of data is it?
• What is the message?

5
Types of Data
• Data values can be numeric or character
(including numbers and symbols).
• Numeric data (such as 2.3 or 12) are used in
positioning features on the graph in a way
proportional to their numeric value.
• Character data (such as "1st Quarter", the year
"2004", or "Resistance, O") are used for
information purposes.

6
Data can be Organized by Categories
• Categories are groupings of data with something
in common.
• Categories are described by one or more character
labels.
• Numeric data for categories are related to the
entries in each category (e.g. number of
occurrences, average, sum, percent, or cumulative
percent).

7
Example of Categorical Data
Character Character Label
Label Numeric
Each row of this table may be considered a
category with two labels.
8
Types of Graphs
• Bar charts (many forms), pie charts, histograms,
and line plots are several of the many ways to
present categorical data.
• Categories are represented on these graphs
independent of any value their label may have as
a number.

9
Bar Chart
10
Pie Chart
Title
Data labels
11
Range Bar Graph
12
Types of Graphs
• Scatter Plots and Contour Plots are used when all
variables are continuous
• Scatter Plots are ideal for experimental data
• Scatter Plots place every point based on the
values of each variable

13
Scatter Plot
Time (sec) Speed (rpm) 1 1210 2 1866
3 2301 4 2564 5 2742
6 2881 7 2879 8 2915 9 ????
10 3010
14
Linear and Logarithmic Scaling
Linear axis
Logarithmic axis
15
Three Common Equation Forms
• Linear
• Y mX B
• Thermal Expansion
• Power
• Y bXm
• Wind Force
• Exponential
• Y bemX
• Population Growth

16
Linear Thermal Expansion of Pipe
L a (T To) Lo L a (dT) Lo (Form Y
mX b)
• T Final temperature
• To Initial Temperature
• Coefficient of thermal
• expansion
• Lo Initial length at
• temperature To
• dT T - To

17
Power Wind Force on Road Sign
• Wind Force on a Sign (F P A)
• P 0.0036 V2
• Where
• P pressure in lb/ft2
• V velocity in ft/sec
• (Form Y bXm)

18
Power Relationship
Linear Form log Y log b m log XY m
X b
Y bXm
19
Exponential Population Growth
Linear Form ln Y ln b m X Y b mX
Y bemX
20
Good Graphing Practices
• Every graph must have a title and axis labels.
• When more than one data set is shown on the same
graph, a legend is needed.
• Leave margins at the edges of the paper.
• Graphs must be neat and easily readable (e.g.
size of graph, large enough font, no text on top
of data or axes).
• Each graph must include the author and date (on
the same page with the graph).

21
What could be improved?
• Bar Spacing
• Title
• Axis labels
• bars

12
10
8
6
4
0
A
B
C
D
22
Are there still problems?
Units produced by Divisions A D in July
10
8
Units In Thousands
6
4
2
0
A
B
C
D
Divisions
23
Example Hand Graph with Data
24
• The overriding objective in making graphs, just
like all forms of Engineering communication is
CLARITY
• Consider the number of traffic fatalities per
year in Ohio (Courtesy NHTSA)

25
Is your message how stable the fatality rate has
been
Traffic Fatalities In Ohio
Number Of Fatalities
Year
Note The Poor Choice of Y-Axis Increment
26
or that fatalities seem cyclical?
Note that zero has been suppressed
27
or?
• Maybe you really wanted to graph traffic
fatalities per 100 million miles driven to show
how safe it is to drive in Ohio.

28
Safe Driving in Ohio
29
College Students with Jobs
• 270 college students were surveyed to find
whether they had part-time jobs and how much they
earned.
• How can we present this data graphically?

30
Pie Chart
31
Earnings Differences for Men and Women
32
Students earning less than 400 per month?
33
Hint
• If you're graphing data to answer a question,
think about which style of graph and which scales
will best show you the answer.