WARM UP
An experiment was designed to investigate the effect of
caffeine on heartbeat in water fleas. Two populations
had all conditions alike except the fleas in population
one had caffeine administered five minutes before
their heart beat was checked. Every two hours both
populations were selected and heartbeats were
monitored.
1. What is the independent variable in the experiment?
2. What is the dependent variable in the experiment?
3. Which group was the control?
Graphing
• Graphs are used to show numerical
information in a useful format.
• There are three main types of graphs:
– circle graphs,
– line graphs
– and bar graphs.
Tables
Tables are used to neatly organize data before placing in a
graph.
Create a table from the following information:
A biology studying a plot of lab in a forest studied the 5
different type of trees in the plot.
Oak- 539
Maple- 758
Beech- 319
Birch- 1,327
Hickory- 222
Circle Graphs/Pie Chart
Shows different parts of the data in relation to
all the data. Useful in depicting percentages.
Bar Graph
A bar graph is used to show data that are not
continuous. Often used for comparisons.
Line graphs
Used to demonstrate continuous change.
When creating a bar or line graph:
• The independent variable is put on the
horizontal (x) axis
• The dependent variable is put on the vertical
(y) axis
• Label your axis and give the graph a title
Let’s Practice
• What kind of graph
should we create from
the following set of data:
Date
Amount of
Precipitation
(cm)
Aug 1
0.5
Aug 2
0.0
Aug 3
1.0
Aug 4
0.25
Aug 5
1.25
Aug 6
0.0
Aug 7
0.0
Aug 8
0.75
Aug 9
1.75
Let’s PracticeYear
Population (in millions)
1880
50.2
1890
62.9
1900
76
1910
92
1920
105.7
1930
122.8
1940
131.7
1950
151.3
1960
179.2
1970
203.2
1980
226.5
1990
251.4
Extrapolate
The process of going beyond the data points. The further
from the data points we extrapolate the less accurate our
findings.
1. Predict what the population of the US will be in
the year 2010.
2. Can you be as certain for this prediction as you
were for a prediction for the year 2000?
3. Use the graph to determine the approximate
population in 1935, 1945, 1985.
Book Scavenger Hunt
1. Find a circle graph/pie chart, a bar graph, and
a line graph in the textbook. (include pg #)
2. Write a short description in your own words
about what the graph tells you.
3. Write one question that could be answered
using the graph.