Date post: | 22-Dec-2015 |
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What is Data?
• Data is information• Examples of data
include:– The number of kilometers
from Houston to Indianapolis
– The number of centimeters of rain that fall yearly in Texas
– The length in minutes of a Hannah Montana song
How is data used?
• Scientists use data all the time to:– Predict the weather– Aid in the recovery of patients in hospitals– Determine the dose of a chemical or radiation
that is harmful to the public
Complete Data Tables Contain:
• A descriptive title
• Variables describing what information has been collected
• Units telling how those variables were measured
• Data collected in ordered pairs
• All work done neatly
The Title
Time (minutes) 0 1 2 3 4 5 6 7 8
Temperature (°C) 20 21 23 27 35 45 61 69 71
Heating of Compound X
• The title of this data table is “The Heating of Compound X.”
• Without a title, it would be difficult for a person studying the table to figure out what all the numbers mean.
Variables and Units
Time (minutes) 0 1 2 3 4 5 6 7 8
Temperature (°C) 20 21 23 27 35 45 61 69 71
Heating of Compound X
• A variable describes what information you are recording.
• A unit tells how you are going to measure that variable.
What is the independent variable? What is the dependent variable?
The Data
Time (minutes) 0 1 2 3 4 5 6 7 8
Temperature (°C) 20 21 23 27 35 45 61 69 71
Heating of Compound X
• Data is organized in a data table.
• The numbers in the table are organized in ordered pairs.
• An ordered pair consists of an independent and dependent variable that correspond to one another.
What is a graph?• A graph is a picture of information in a data table.• The following data table and graph are for the Heating of
Compound X.
Time (minutes) 0 1 2 3 4 5 6 7 8
Temperature (°C)
20 21 23 27 35 45 61 69 71
Heating of Compound X
Heating of Compound X
0
20
40
60
80
1 2 3 4 5 6 7 8 9
Time (minutes)
Te
mp
era
ture
(d
eg
ree
s
C)
What do the table and graph have in common?
Everything! They contain the same title, variables, units, and data.
Time (minutes) 0 1 2 3 4 5 6 7 8
Temperature (°C)
20 21 23 27 35 45 61 69 71
Heating of Compound X
Heating of Compound X
0
20
40
60
80
1 2 3 4 5 6 7 8
Time (minutes)
Te
mp
era
ture
(d
eg
ree
s
C)
Graphs
• The independent variable goes on the horizontal axis, or X-axis.
• The dependent variable goes on the vertical axis, or Y-axis.
0 1 2 3 4Time (minutes)
20
10Temp.(°C)
0
Intersection for ordered pair (1, 21)
What type of graph should I use?
• One of the most challenging parts of graphing data is to decide which type of graph is appropriate for the data.
• There are three main types of graphs that are often used for scientific data: pie charts, bar graphs, and line graphs.
Pie Charts
• Pie charts, or circle graphs, are used to display what part of a whole each variable is. Pie charts are ideal when showing fractions or percents.
Bar Graphs
• Bar graphs show how variables compare to one another.
• Bar graphs look at the differences between similar things.
Line Graphs
• Line graphs show how a variable changes, usually with time as the independent variable.
0
50
100
150
200
250
300
350
400
0.5 1 1.5 2 2.5 3 3.5
distance from detector (in)
Co
un
ts p
er m
inu
te (
cpm
)
What type of graph should I use?
Look at the following example and decide which type of graph will best fit the data.
How many pets does the average family have?
Answer: A Bar Graph
What type of graph should I use?
Look at the following examples and decide which type of graph will best fit the data.
What type of trash makes up the biggest portion of garbage?
Answer: A Pie Chart
What type of graph should I use?
Look at the following examples and decide which type of graph will best fit the data.
How much will the temperature of a turkey change when baking for twenty minutes?
Answer: A Line Graph
Game Time!
• Now it’s time to collect our own data and generate a graph.
• We will be measuring the number of seconds it takes to pass the beanbag ball from student to student. We will start with five students and continue adding five students until the whole class is passing the ball.
What is missing?
0
50
100
150
200
250
300
350
400
0.5 1 1.5 2 2.5 3 3.5
distance from detector (in)
Co
un
ts p
er m
inu
te (
cpm
)
What is missing?
Problem Areas
0
5
10
15
20
25
30
35
40
Tran
smiss
ion
Fuel
syste
m
Misc
ellan
eous
Noisy
Driver
cont
rols
Other
elec
trica
l
Ignit
ion
Coolin
g sy
stem
Brakin
g
Emiss
ions
Steer
ing