Bell Ringer When completing an experiment, you are testing your hypothesis. What are the three kinds of variables that you need to identify in your experiments? A: independent, controlled, and dependent B: independent, dependent, and identical What is the independent variable? A: the variable that you purposely manipulate B: the variable that is being observed C: the variable that is not changed
What is the controlled variable? A: the variable that you purposely manipulate B: the variable that is being observed C: the variable that is not changed How many independent variables can you have during an experiment? A: 1 B: 2 C: as many as you would like D: the same amount as the number of controlled variables How many controls can you have in an experiment? A: 0 B: 1 C: 2 D: as many as you would like
Types of Graph And when to use them!
Bar Graph
Bar Graph Used to compare amounts in data that represent different categories (discrete data sets) Often times “category” is plotted on X-axis, number values) on the Y-axis Often used incorrectly to graph data with continuous X variables
Line Graph
Line Graph Used to show trends Variable plotted on X (bottom) musts be continuous Common type is “time series” where X = time CANNOT be used to graph data where X is discrete
Scatterplot
Scatterplot Used to show relationships between variables X variable must be continuous If one variable is believed to cause or explain changes in the other, that variable is plotted on the X
Histogram
Histogram Used when discrete X is converted to categories (“bins”) Y represents frequency of data within each “bin”
Pie Chart
Pie Chart Used for same kind of data as bar chart Each slice = data category Slice size shows relative proportion of observations within each category
Summary: Types of Graph Graph type Use Line graph Connects dots with lines Used for continuous X data Show patterns or trends If time = X, time-series graph Scatterplot Display relationship between variables Line of Best Fit or Trend Line Bar graph Used to show patterns Should only be used when X data are categorical or discreet
Graph type Description Histogram Similar to bar graph, but used when continuous X data are converted to categories Pie chart Compares small number of categories. Works best if values are very different. If similar, should label pie segments with actual values