Graphing Your Data Showing patterns trends A picture

Graphing Your Data Showing patterns & trends A picture is worth a thousand words! Regents Biology 2008 -2009

Types of data (information) § Variables what you measure in an experiment u dependent variable u § What is measured § unpredictable change: we don’t know how it will change until we do the experiment § Y-axis u independent variable The effect of INDEPENDENT _______ on DEPENDENT _______ § What is changed variable § predictable change: it only changes because we chose how it would change Regents Biology§ X-axis 2005 -2006

Examples of experiments 1 § How does fertilizer affect the growth rate of plants? u we set up an experiment testing different amounts of fertilizer on different plants & measuring the growth (height) of the plants: § dependent variable (Y-axis)? w height of plants § independent variable (X-axis)? w amount of fertilizer Regents Biology The effect of Amount of Fertilizer _______ on Height of Plants _______ 2005 -2006

Examples of experiments 2 § How does exercise affect heart rate of 10 th grade student? u we set up an experiment testing different lengths of time of exercise (minutes) on the heart rate of students: § dependent variable (Y-axis)? w heart rate § independent variable (X-axis)? w minutes of exercise Regents Biology The effect of Exercise _______ on Heart Rate _______ 2005 -2006

Examples of experiments 3 § What’s the favorite drink of students? u we set up an experiment surveying students and asking which is their favorite drink : § dependent variable (Y-axis)? w number of students § independent variable (X-axis)? w type of drink The effect of Type of Drink _______ on How many students chose it _______ Regents Biology 2005 -2006

The Dependent Variable is dependent on the Independent Variable! Which is which? Growth of Plant Amount of Light Regents Biology 2005 -2006

Making pictures out of data How’s a critter § Graphs u line graphs to choose? § graphing data that shows continuous change u bar graphs (or histograms) § graphing data that is in disconnected groups § The bars touch for a histogram and are separated for a bar graph Regents Biology 2005 -2006

How does elevation affect temperature? Line graph! 30 elevation (feet above sea level) temp. (°C) 0 30 500 25 1000 20 1500 15 2000 10 2500 5 temperature 25 20 18 15 10 1200 ft? 5 0 0 Regents Biology 500 1200 1500 1000 elevation 2000 2500 2005 -2006

Which drink do you like best? number of students 6 Bar graph! 5 4 drink number Coke 1 Pepsi 1 Water 4 Iced tea 4 Gatorade 3 3 2 Red Bull? 1 0 RB Pepsi. RB water Coke Regents Biology type of drink tea Gatorade 2005 -2006

We took a tally of how many students like each kind of pop… Make a bar graph to show the results Pepsi 15 Coca Cola 12 7 -Up 4 Mountain Dew 8 Root Beer 2 Cherry Coke 7 Dr. Pepper 5 Regents Biology 2005 -2006

This table shows how student attendence effects their grades… Make a line graph of the data Number of Days Missed during year Regents Exam Grade 5 88 10 80 14 74 22 68 36 55 50 52 78 34 Regents Biology 2005 -2006

Questions: (write this on your graph paper) § What is the independent variable? u Number of days absent § What is the dependent variable? u grade § What is the relationship between number of days missed and grade? u As the number of days absent increases, Exam grade decreases! Regents Biology