Post on 02-Jan-2016
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Data Collection, Accuracy, & Precision
Data Collection There is __ __ ____ as a perfect __________.
Each measurement contains a degree of uncertainty due to the _____ of ________ and the people using them.
When an experiment is performed, it is necessary to _______ collect ____so that a correct ________ can be determined.
Aspects of Proper Data Collection
Things to be considered in collecting data:• Using the proper __ ______
Example: centimeters, not inches
• Recording units with each measurement
Always include _ ______!!!
• Using the appropriate __________ Example: graduated cylinder, not beaker
• __________ reading the instrument
Example: knowing what each line on a metric ruler represents
• Writing down the known ______ of the ________ plus the ________ digit
Example: making a length measurement, and estimating the last digit as either 0 or 5
Aspects of Proper Data Collection (continued)
Accuracy & Precision _______ is how _____ a measurement, or
___________ value, is to an accepted value, or ________.
________ is how close a set of measurements are to ____ ________.
Seeing Accuracy & Precision
Determining Trends in Data
Trends When analyzing a graph, the
ways that the data sets (dependent variable and independent variable) relate to one another are called ______
Trends can also be seen as “________” in your data
Types of trends• ______ Relationship• ______ Relationship
Rainfall versus Time
0
20
40
60
80
100
120
140
1975 1980 1985 1990 1995 2000 2005
Time (Years)
Rai
nfa
ll (c
m)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 2 4 6 8 10
Pla
nt
He
igh
t (c
m)
Fertilizer added (g)
Plant Height vs. Fertilizer Added
0
1
2
3
4
5
6
7
8
9
0 1 2 3 4 5
Pla
nt H
eig
ht (
cm)
Acid Added (mg)
Plant Height vs. Acid Added
_________ Relationship
When the dependent variable and the independent variable both ______/______
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 2 4 6 8 10
Pla
nt
He
igh
t (c
m)
Fertilizer added (g)
Plant Height vs. Fertilizer Added
________ Relationship
When one of the variables _______ as the other __________
0
1
2
3
4
5
6
7
8
9
0 1 2 3 4 5P
lan
t Hei
gh
t (cm
)
Acid Added (mg)
Plant Height vs. Acid Added
Stating the Trend
Instead of simply saying if a relationship is _______ or _______, we can put the _____ into a sentence using the format below:
• As the “_______ ________” increases/decreases the
“_________ __________” increases/decreases.
(choose one)
(choose one)
Practice
As the _____________
increases/decreases the
_____________
increases/decreases.
(circle one)
(dependent variable)
(independent variable)
(circle one)
Rainfall total versus Time
012345678
1965 1975 1985 1995 2005
Time (Years)
Rain
fall
(cm
)
WRITE YOUR OWN TREND STATEMENT
Mosquitos versus Time
050100150200250300350400450
1970 1975 1980 1985 1990 1995 2000
Time (Years)
Mos
quito
Bite
s
(# p
er c
ity)
PracticeRainfall total versus Time
012345678
1965 1975 1985 1995 2005
Time (Years)
Rain
fall
(cm
)
Mosquitos versus Time
050100150200250300350400450
1970 1975 1980 1985 1990 1995 2000
Time (Years)
Mos
quito
Bite
s
(# p
er c
ity)
Based on your two trend statements, do you see a connection between the amount of
rainfall and the number of Mosquito incidents?
What if there isn’t a distinct trend?
If you find that a trend is ___ clear with your graph, you should assess it based on where the pattern lies• Look at the
_______/________ direction of the graph
• Try to fit a line that will go in between the points…
And assess from there
Rainfall versus Time
0
20
40
60
80
100
120
140
1975 1980 1985 1990 1995 2000 2005
Time (Years)R
ain
fall
(cm
)
Using Graphs _____________
• the ability to __________ data within a given ______ of collected data
Using Graphs ___________
• The ability to estimate data beyond the ________ of collected data