Data Collecting, Organizing & Analyzing. VARIABLES & DATA TABLES.
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Transcript of Data Collecting, Organizing & Analyzing. VARIABLES & DATA TABLES.
Data Collecting, Organizing &
Analyzing
VARIABLES & DATA TABLES
In an experiment there are 2 types of variables• INDEPENDENT VARIABLES
&
•DEPENDANT VARIABLES
a VARIABLE is any factor, or thing that can change during your experiment
a CONTROLED experiment only has 1 variable changing, or being tested
Sometimes a control trial or group is used to compare experimental data to
INDEPENDENTVARIABLE
This is the variable we can control in an experiment.
Independent variables are set up ahead of time, before you start following your procedures
INDEPENDENTVARIABLE
In a “T” table, or data table, this variable is on the left side.
On a graph, this variable goes on the X axis
INDEPENDENT VARIABLE Examples of common
Independent variables:• Time-measure every 30
seconds, every day, etc.• Distance-measure every 0.5
meters, every 10.0 cm• Amount-add 2.0 grams each
trial
INDEPENDENTVARIABLE
Your book calls the independent variable the MANIPULATED variable, because we manipulate or set it to our specifications
DEPENDENTVARIABLE
This is the variable we have to observe in an experiment.
Dependent variables are measured during the experiment, after you start following your procedures
DEPENDENTVARIABLE
In a “T” table, or data table, this variable is on the right side.
On a graph, this variable goes on the Y axis
DEPENDENT VARIABLE Examples of common
Dependent variables:• Temperature-record the
temperature• Mass-find the mass of each
object or substance• Amount-count the resulting
number of items
DEPENDENTVARIABLE
Your book calls the dependent variable the RESPONDING variable, because it responds to the procedure you are following. We can’t chose what the data will be.
GRAPHING NOTES
7 RULES OF GRAPHING
Follow these simple rules for GREAT GRAPHS
RULE # 1.
1. Always draw neat lines with a straight edge or ruler
RULE # 2. Make your graph 1 full page
in size. Small graphs are too difficult
to read patterns or results of your experiment.
RULE # 3. Label the x-axis (goes across
the bottom of your graph) Label the y-axis ( the line that
goes up & down on the left side of your graph)
RULE # 4. Label three places on your
graph. 1. TITLE the graph
descriptively WHAT DOES YOUR
GRAPH SHOW US?
RULE # 4. 2. label the x-axis with the
independent variable• this is the variable you pre-set before
you began collecting data, on the left side of a “T” table
• common independent variables can be time, or distances
• Data points should be evenly spaced
RULE # 4. 3. label the y-axis with the dependent
variable• this is the variable you measure when
you begin collecting data, on the right side of a “T” table
• common dependent variables can be mass, or temperature
• Data points should be evenly spaced
RULE # 5. Number the x and y axis with
a regular numerical sequence or pattern starting with 0 to space out your data so it fills the entire graph• examples: 0, 5, 10, 15 . . .
• 0, 2, 4, 6, . ., 0, 0.5, 1.0, 1.5, 2.0
RULE # 6. Number the x and y axis on
the lines of the graph, not the spaces between the lines
RULE # 7. If your graph shows more
than one trial of data, or has more than 1 line, USE A KEY
A key can be different colored lines, lines with different textures or patterns.
Choose the best graph for the data
Pie chart- shows percentages and parts of a whole
Bar graph- best for comparing data Line graph- best for looking at change over
time Stem & Leaf plot- comparing data that can
also show mean, mode, and median
Statistical Analysis Mean- (average)- add up all the data & divide that
total by the number of data points ex. : 1,2,3,2,4,2 = 14 14/6= 7/3 or 2.3
Mode- number seen most often ex:1,2,3,2,4,2 mode is 2
Median- middle value when data is placed in numerical order Ex.: 1,2,2,2,3,4,5 odd
ex:1,2,2,2,3,4 even 2+2=4/2=2 median is 2 Range- difference between the greatest # and the
smallest # in the data set ex.1,2,2,2,3,4 4-1= 3 data vary over 3 values
How to change numbers into % for pie charts. You can refer to your book on page 770. Determine the total number for your data: add up all the
values to get one number. 1,2,2,2,3,4 = 14 Divide each proportion by the total number. 1/14, 2/14.
3/14, 4/14 Multiply that decimal by 360. This will give the number
of degrees that your pie piece should contain. Ex. 2/14= 0.143 0.143 x 360= 51.4 degrees
Use a protractor to measure the angle of each slice. To find the percentage take the number of degrees in the
slice divide it by 360 and multiply the new number by 100%. 51.4 / 360= 0.143 x 100% = 14.3 %
The EndGood Luck and Happy Data
Collecting!