Column charts   

o    Vertical bar charts

o    Clustered – compares values across categories using vertical rectangles

o    Stacked – displays contribution of each value to the total by staking the rectangles

o    100% stacked – compares the percentage that each value contributes to the total

o    Horizontal column chart

Line chart

o    Connects points of data via a line

o    Provides useful means for displaying data over time

Pie chart

o    Displays the relative proportion of each data source to the total

Area chart

o    Combines a pie chart and a line chart

o    Looks like a line chart (total) with the bottom colored in depending on the contribution of each part to the total

Scatter diagrams

o    Show the relationship between two variables

o    Plotted points

Stock chart

o    Plots stock prices, such as daily high, low, and close

 Surface chart

o    Shows three-dimensional data

Doughnut chart

o    Similar to a pie chart but can contain more than one data series

Bubble chart

o    Type of scatter chart in which the size of the data marker (point) corresponds to the value of a third variable

Radar chart

o    Plots multiple dimensions of several data series

Descriptive statistics

o    Refers to a collection of quantitative measures and ways of describing data

Arithmetic mean

o    Average

o    Measure of central tendency

Outliers

o    Rare observations that are radically different from the rest

Median

o    The middle value when the data are arranged from smallest to largest

o    Measure of central tendency

Mode

o    Observation that occurs the most

o    Measure of central tendency

Midrange

o    The average of the largest and smallest values in a data set

o    Measure of central tendency

Dispersion

o    The degree of variation in the data

o    The numerical spread (or compactness) of the data

Range

o    The simplest measure of dispersion

o    Computed as the difference between the maximum and the minimum values

Variance

o    Measure of dispersion

o    Depends on all the data

o    The formula used is different for populations and sample     

 Standard deviation

o    Measure of dispersion

o    The square root of the variance

·         Chebyshev’s theorem

o    States that for any set of data, the proportion of values that like within k standard deviations (k>1) of the mean is at least 1-1/k2

o    For k = 2, at least ¾ of the data lies within 2 standard deviations of the mean

o    For k = 3, at least 89% of the data lie within 3 standard deviations of the mean

·         Coefficient of variation (CV)

o    Provides a relative measure of the dispersion in data relative to the mean

o    CV = standard deviation/mean

·         Frequency distribution

o    Tabular summary showing the frequency of observations in each of several non-overlapping groups, or cells (called “bins”)

o    Graphical depiction of a frequency distribution in the form of a column chart

·         Relative frequency

o    The fraction that falls in each interval of observations

·         Cumulative relative frequency

o    The sum of all the relative frequencies at or below each upper limit

o    Represents the proportion of the sample that falls at or below the upper limit value

·         Coefficient of skewness (CS)

o    Measures the degree of asymmetry of a distribution around its mean

o    + = positively skewed

o    - = negatively skewed

the closer the CS is to zero, the less the degree of skewness of the distribution

·         Unimodal

o    Distributions that have only one peak

·         Bimodal

o    Distributions that have two peaks

·         Kurtosis

o    Refers to the peakedness or flatness of a distribution

·         Coefficient of Kurtosis (CK)

o    Measure the agree of kurtosis of a population

o    <3 more flat, with a wide degree of dispersion

o    >3 more peaked, les dispersion

·         Correlation

o    Measure of a linear relationship between two variables , x and y

·         Correlation coefficient

o    Measure the correlation of a population

o    + = As one variables increase, so does the other

o    - = As one variable increases, the other decreases

·         Box-and-whisker plots

o    Graphically displays the five key statistics of a data set (min, 1^st quartile, median, 3^rd quartile, max)

o    Useful to identify the shape of a distribution and outliers of data

·         Interquartile range

o    Q3 – Q1

o    Also known as mid-spread

·         Stem-and-leaf display

o    Classifies data into cells, similar to a histogram, but at different levels of aggregation as defined by the stem unit

·         Dot-scale diagrams

o    Show a histogram of data values as dots corresponding to individual data points, along with the mean, median, 1^st and 3^rd quartiles, and +/- 1, 2, and 3 standard deviations

·         Proportion

o    The formal statistical measure of a fraction of data that have a certain characteristic

·         Cross-tabulation

o    A tabular method that displays the number of observations in a data set for different subcategories of two categorical variables

·         Contingency table

o    A cross-tabulation table