DESCRIPTIVE STATISTICS

Descriptive statistics are the values that describe the data. Values like mean, median or mode are used to help us describe measures of center.  Graphical displays are used to help see what the data is telling us. Variance and standard deviation help to describe the variability of the data. Quartiles, percentiles, and z-scores help us with measures of position. Range and interquartile range are use to describe the spread of the data. Watch videos below to help see some of these in action.

Graphical Displays

Learn different techniques of displaying statistical data. Learn how to create histograms, box plots, dot plots, stem and leaf plots, and Pareto charts.  Explore how to create frequency distributions, including frequency, relative frequency, and cumulative frequency.  All graphs will be shown by hand and with technology using TI-84 and TI-Nspire graphing calculators.

Creating a Frequency Distribution
Creating a Frequency Histogram
Creating a Relative Frequency Histogram
Relative Frequency TI-84
Creating a Histogram and Frequency Distribution with TI-84
Relative Frequency TI-Nspire
Use a Frequency Histogram to Answer Questions
Creating a Frequency Distribution and Histogram TI-Nspire
Finding the Frequency and Class Limits with the Help of Excel
Using Excel to Find Midpoint, Relative Frequency, and Cumulative Frequency
Creating an Ogive (Cumulative Freq. Graph)
Creating an Ogive Using Cumulative Relative Frequency
How to Create a stem and Leaf Plot (Stemplot)
How to Create a Dot Plot
Box (Box and Whisker) Plot by Hand
Box (Box and Whisker) Plot Using the TI-84
Box (Box and Whisker) Plot in TI-Nspire
Box (Box and Whisker) Plot in Excel
Boxplot and Five Number Summary using ClassCalc
Bar Chart and
Pareto Chart
Pie Chart
Pie Chart and Bar Graph in the TI-Nspire
Creating a Histogram in Excel with Midpoint and Frequency
Building Descriptive Statistics in Excel
Building a Frequency Distribution in Excel
Alternative Histogram in Excel
Inserting a Histogram into Excel Sheet - 2 methods
Creating a Frequency Polygon
Using a Frequency Polygon to Answer Questions
Using a Circle Graph to Find Cost
Creating a Pie Chart in Excel
Creating a Scatter Plot
Creating a Scatter Plot in the TI-84
Creating a Scatter Plot in the TI-Nspire

Measures of Center

This is also known as the measures of central tendency.  The measures of center are the mean, median, and mode. All three are ways of interpreting the center of the data values.  The median is resistant to outliers and is used the most often with data that is skewed to the right or left. The mean is influenced by outliers and is best used when the data is roughly symmetric.  The mean will always be pulled toward the outlier. The mode is the data value that occurs the most frequently. There are different situations that require the use of each of three measures. 

Finding the Mean
Finding the Median
Finding the Mode
Finding the Mean and Median with the TI-Nspire
Finding the Mean and Median with the TI-84
Finding a Weighted Mean
Finding a Weighted Mean Using the TI-Nspire
Finding a Weighted Mean Using the TI-84
Weighted Mean in Excel
Approximating the Mean of a Histogram TI-84
Approximating the Mean of a Histogram TI-Nspire
Finding Mean, Median, Mode, and Sample Standard Deviation in Excel
Use ClassCalc to Find the Mean, Median, and Mode
Use ClassCalc to Find the Mean of a Frequency Distribution

Measures of Variation

The measures of variation help us to see how much variation our data values have.  Sometimes this is also called measures of spread.  Common measures of variation are range, deviation, standard deviation and variance.  The following videos will help us to find the common measures of variation.

Population Variance and Standard Deviation by Hand
Sample Variance and Standard Deviation by Hand
Variance and Standard Deviation with the TI-84
Variance and Standard Deviation with the TI-Nspire
Variance and Standard Deviation with Excel
Variance and Standard Deviation with ClassCalc
Sample Mean, St. Dev., and Variance of a Frequency Distribution by Hand
Sample Mean, St. Dev., and Variance of a Frequency Distribution TI-84
Sample Mean, St. Dev., and Variance of a Frequency Distribution TI-Nspire
Sample Mean, St. Dev., and Variance of a Frequency Distribution in Excel

Measures of Position

The measures of position break our data into fractals like quartiles and percentiles. Learn what quartiles are and how to find them. Percentiles are useful in comparing things. Z-scores are also a measure of position because they tell us how many standard deviations a value is from the mean, so we can determine if they are unusual or not.

Quartiles
5-Number Summary TI-84
5-Number Summary TI-Nspire
5-Number Summary Excel
What is a z-score?
Finding and Comparing z-Scores
Finding Number of Data w/in 1, 2,or 3 St. Deviations Using Excel
Empirical Rule or 68-95-99.7 Rule
Empirical Rule (68-95-99.7 rule) to Find Percentile