240 likes | 337 Views
Section 2.2. More Graphs and Displays. Stem-and-Leaf Plots. Each number is separated into a STEM and LEAF component. The STEM is the leftmost digit(s). The LEAF is the rightmost digit. It’s important to include a key to identify values. For example… Key: 15 | 5 = 155.
E N D
Section 2.2 More Graphs and Displays
Stem-and-Leaf Plots • Each number is separated into a STEM and LEAF component. • The STEM is the leftmost digit(s). • The LEAF is the rightmost digit. • It’s important to include a key to identify values. For example… Key: 15 | 5 = 155
Make a stem-and-leaf plot: • Ages of the top 30 highest paid CEOs (Forbes Magazine).
Pie Chart (for Qualitative Data) • A circle divided into sectors that represent categories. • The area of each sector is proportional to the frequency of the category. • Find RELATIVE Frequency and multiply by 360o to get the central angle for each category.
Use a Pie Chart to display data • 2010 NASA budget request (in millions of dollars)
Pareto Chart (for Qualitative Data) • Vertical bar graph in which the height of each bar represents the frequency or relative frequency. • Bars are positioned in order of decreasing height, left to right. • EX: Make a Pareto chart • Ultraviolet indices for 5 cities at noon:
Scatter Plot (for Paired Data Sets) • Paired data Ordered pairs. • Plot on a coordinate plane. • Independent variable on the x-axis.
Section 2.3 Measures of Central Tendency
Measure of Central Tendency: • A value that represents a typical, or central, entry of a data set. • 3 most common are MEAN, MEDIAN, and MODE
MEDIAN • The data entry in the MIDDLE. • List data from least to greatest. • Find the middle value. • (For even n, find the average of the 2 middle values)
MODE • Data entry that occurs MOST often (highest frequency) • A data set may have no mode or have more than mode. • BIMODAL = 2 modes.
Shapes of Distributions • Distributions may look .. • Symmetric • Uniform • Skewed Left • Skewed Right