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