HOME WORK WEB PAGE FOR CLASS MATH 251 & MATE 251 & MATE 345

MAIN PAGE

Chapter 3 Descriptive Statistics

 

3.4 Exploratory Data Analysis

 

In this section we continue exploratory data analysis by considering five-number summary and box plots.

 

            Five-Number Summary

           

1.      Smallest Value

2.      First Quartile Q1

3.      Second Quartile Q2 (median)

4.      Third Quartile Q3

5.      Largest Value

 

Box Plot

A Box Plot is a graphical summary of data based on a five-number summary.

All we are trying to do is identify values that may not belong in the data set.

Just a reminder IQR=Q3-Q1

 

Please See the Box Plot for SalarySummary.pdf file

 

Please Go This Link to make a box plot for any set of data. It is pretty neat application!!!!

http://www.physics.csbsju.edu/stats/bulk.stats.n.plot_NGROUP_form.html

 

Enter 1 for the number of group. And try to do for Salary.xls file.

 

Home Work

1.      Provide the 5 number summaries for the values 27, 25, 20, 15, 30, 34, 28, and 25.

2.      Show the Box Plot for the data in 1.

3.      A data set has a first quartile of 42 and a third quartile of 50. Compute the lower and upper limits. Should a data value of 65 be considered an outlier?

4.      Here (ReEquity.xls) are the return on equity percentage for 25 companies (Standard & Poor’s Stock Reports, Now 1997)

a.      Provide a five-number summary

b.      Compute the lower and upper limits

c.      Do there to be outlier? How would this information be helpful to a financial analyst?

d.      Show a box plot

5.      Birinyi Associates, Inc., conducted a survey of stock market around the world to asses their performances during 1997.  (World.xls) summaries the findings for a sample of 30 countries.

a.      What are the mean and median percentage changes for these countries

b.      What are the 1st and 3rd quartiles (Q1? Q2?)

c.      Are there any outliers? Show a box plot

d.      What percent would you report for the USA

 

Using Excel’s Descriptive Statistics Tool

 

These steps will help you to compute one statistics at once. Starting Salary Data (Salary.xls) as we describe the steps involved.

 

Step 1. Select Tools pull-down menu

Step 2. Choose Data Analysis

Step 3. Choose Descriptive Statistics from the list of Analysis tools

Step 4. When the Descriptive Statistics dialog box appears:

                        Enter A1:A13 in the Input Range box

                        Select Grouped By Columns

                        Select Labels in First Row

                        Select Output Range

                        Enter in the Output Range box

                        Click OK