Warm up 9/17

• What are the metric prefixes which we remember withking Henry Died by drinking Chocolate Milk

• What percentage of the world’s countries use metric?

• When is the first Exam?– When is the Study Guide Due?

Notes: Graphing

Setting Up a Graph

• X axis- Independent Variable – This is the variable you

controlled or manipulated.

• Y axis- Dependent Variable– This is the variable

measured or observed during an experiment

Graphing Rules

Rule #1Use a Pencil!

Rule #2Always draw

neat lines with a ruler or straight edge.

Rule #3Label the X-axis(independent variable)

and y-axis (dependent variable)

And include UNITS!• Example: If your X-axis is

labeled “TIME,” you must put the unit in parentheses (hours, days, years, etc.)

Rule #4Use an appropriate

scale for each axis• Graph must take up at least 75% of

given space• Graphs do not have to start at zero

if your data does not include zero.

Rule #5Title your graph

Rule #6Provide a key (color or pattern) when using the

same graph for multiple independent variables.

Best Fit Line

If the points form a straight line…..draw the best straight line through them.

Best Fit Line• The best fit line is the straight line that is closest to all points.

– If you measured the distance from the line to all points and added the distance together, this is line which has the smallest sum.

• If a point is not on the line …..

Re-test this measurement again if applicable.

x

x

x

xx

xThis is called an anomalous point or outlier.

You can decide to ignore anomalous points.

Curved Graphs

• If the points form a curve….Draw a free hand curve of best fit.

J-Curve:Usually shows slow then rapid growth of a population

Curved Graphs

• If the points form a curve….Draw a free hand curve of best fit.

S-Curve:Shows slow then rapid growth until the population stabilizes