Graphs

V. Data Analysis

A. Range 1. Total value your data covers from lowest to highest2. Range = highest value – lowest valueex. Data is 2 5 7 14 19Range = 19 – 2 = 17

B. Average1. The mean of all the data values collected2. Avg = total of values

# of values addedex: Data is 2 5 7 14 19

Avg = 2 + 5 + 7 + 14 + 19 = 47 = 9.45 5

VI. GraphsA. Visual way to organize and analyze data

B. Types of graphs:

1. Line

2. Bar

3. Pie

C. Line graph1. Used when one variable causes a second variable to increase or decrease in value2. Often show changes over time

D. Bar graph

1. Compares categories of information2. Good for surveys

E. Pie graphs

1. Compares categories of information usually written in percent2. Slices must add

up to 100%

Practice: Name these graph types

0

20

40

60

80

100

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

Chart #1

East

West

North

Chart #2

1st Qtr

2nd Qtr

3rd Qtr

4th Qtr

Chart #3

0

20

40

60

80

100

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

East

West

North

4.Which type of graph and why?Dog Breed % of dog owners who

own this

breed of dog

Golden Retrievers 30%

German Shepherd 20%

Beagle 20%

Poodle 20%

Rottweiler 10%

Pie GraphPercent with total adding up to 100%

5. Which type of graph and why?

Bar graphComparison survey

First Name # of Letters

Jasmine 7

Alejandra 9

Kenji 5

Lola 4

Jordan 6

F. Variables

2. Dependent variable – variable influenced by independent variable

a. Always on y-axis (vertical line)

b. No one controls

1. Independent variable – variable that might influence another variable

a. scientist changes b. always on x-axis (horizontal line)

G. Making a line graph1. Choose variables for your x and y-axis

a. x variable causes change in y variable

b. Label your axes with titles, numbers, and units

2. Make a scale

a. Scale = range # of boxes = # data units per graph

box

3. Plot your data

4. Create a descriptive title putting the y variable first

PracticeA student counted the total number of leaves in a group of duckweed plants over a 5 day period. Copy this data into your notes.

Days Number of Leaves

0 15

1 20

2 25

3 40

4 60

5 80

1. What is the independent variable?2. Which axis does it go on?3. What is its range?4. On a 10 x 10 box grid, what is its scale?5. Number and label your axis.

0 1 2 3 4 5 6 7 8

Days

6. What is the dependent variable?7. Which axis does it go on?8. What is its range?9. On a 10 x 10 box grid, what is its scale?10. Number and label your axis.

100908070605040302010

0

Nu

mb

er o

f L

eave

s

11. Now plot your data points and draw a straight line through them.

12. Write a descriptive title for this graph.

13. When would the plants have 35 leaves?

14. How many leaves would the plants have after 7 days?

H. 3 Types of Graphing Relationships

1.Direct Relationship

a. When one variable increases, the other increases.b. If one variable decreases, so does the other one.c. or

draw this as example

2. Inverse Relationshipa. When one variable increases, the other decreases

b.

draw this as example

3. No Relationshipa. Data points are scattered all over

draw this as example

Direct Inverse