univariate data

Univariate Data

Chapters 1-6

UNIVARIATE DATA• Categorical Data• Percentages• Frequency Distribution, Contingency Table,

Relative Frequency Bar Charts (Always for comparison, Pie Charts, Segmented Bar Charts.

• Quantitative Data• Dot Plots, Stem Plots, Box Plots, Histograms,

Cumulative Frequency Histogram

Male53%

Female47%

Gender of StudentsGermantown Academy Senior Class

Another Graphical Display for Categorical Data is a Pie Chart

Grade No Yes9 80% 20%

10 68% 32%11 68% 32%12 64% 36%

Contingency Tables and Segmented Bar Charts

Grade No Yes Total9 20 5 25

10 17 8 2511 17 8 2512 16 9 25

9 10 11 120%

20%

40%

60%

80%

100%

120%

Students Who Enjoy Cafeteria Food

No Yes

Frequency Table Relative Frequency Table

Quantitative DataDistribution: Center, Shape, Spread, Outliers

Measures of Center: Mean, Median, Mode

Measures of Spread: Range, IQR, Standard Deviation

Mean goes with Standard Deviation, Median goes with IQR

Use mean and standard deviation when distribution is unimodaland symmetric

Outlier Rule = 1.5 x IQR

Addition/Subtraction changes only measures of Center

Multiplication/Division changes measures of Center and Spread

From an Ogive be prepared to find the median and IQR

Comparing Distributions

Describing Shapes of Distributions

Remember!•If distribution is unimodal and symmetric, the mean end median will be approximatelythe same•If the distribution is skewed right, the mean will be to the right of the median•If the distribution is skewed left, the mean will be to the left of the median•Skewed distributions tend to have more variation than symmetric distributions