Chapter 2 - Graphical Descriptive Statistics PDF

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Download Chapter 2 - Graphical Descriptive Statistics PDF

Description

Graphical Descriptive Statistics Interval Data: -

Known as quantitative or numeric data Numbers that have a meaning o Age, years of schooling, wage, GDP, exchange rate

Ordinal Data: -

Numbers denote ordered categories Only the order matters o Highest Degree Completed  1 (none), 2 (elementary), 3 (high school), 4 (university) o Course Evaluation:  1 (poor), 2 (fair), 3 (good), 4 (very good), 5 (excellent)

Nominal Data: -

Known as qualitative or categorical data Numeric values just denote a name or category Have no meaning as a number o Sex: 0 (male), 1 (female) o Postal Code

Frequency: -

Number of observations falling into a group or category

Relative Frequency: -

Proportion of observations falling into a group or category

Cumulative Relative Frequency: -

Proportion of observations falling into a group and all previous groups o Applies only to ordered groups o Applies to Ordinal, but not Nominal data

Bar Chart/Graph: -

Uses bar heights to display frequencies for each group

Relative Frequency Bar Chart: -

Same as Bar Chart/Graph except that it displays relative frequencies

Pie Chart:

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Uses the size of triangles to display relative frequencies

Hint: -

Make frequency/relative frequency tables then use tables to make charts

Histograms: -

Nominal and Ordinal data have pre-defined groups which is easy to calculate frequencies and plot bar charts Interval data has no pre-defined groups which will then be defined as classes and calculate frequencies of those classes and plot a histogram

Shapes of Histograms: -

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Symmetry: o If a vertical line is drawn down the center for the histogram, the two sides should be identical in shape and size Skewness: o A skewed histogram is one with a long tail extending to either the right or left Modality: o A unimodal histogram is one with a single peak o A bimodal histogram is one with two peaks Bell Shape: o A symmetric unimodal histogram is one that is bell-shaped

Cross-Sectional Data: -

Observations measured at the same point in time

Time-Series Data: -

Observations measured at successive points in time Graphed on a line chart o Plots the value of the variable on the vertical axis against the time periods on the horizontal axis...