 Data Collecting, Organizing & Analyzing

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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

INDEPENDENT VARIABLE This is the variable we can control in an experiment. Independent variables are set up ahead of time, before you start following your procedures

INDEPENDENT VARIABLE 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

INDEPENDENT VARIABLE Your book calls the independent variable the MANIPULATED variable, because we manipulate or set it to our specifications

DEPENDENT VARIABLE This is the variable we have to observe in an experiment. Dependent variables are measured during the experiment, after you start following your procedures

DEPENDENT VARIABLE In a “T” table, or data table, this variable is on the right side. On a graph, this variable goes on the Y axis

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

DEPENDENT VARIABLE 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, 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, = 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 This will give the number of degrees that your pie piece should contain. Ex. 2/14= 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% / 360= x 100% = 14.3 %

Good Luck and Happy Data Collecting!
The End Good Luck and Happy Data Collecting!