1. BUS304 – Data Presentation1 Group Data and Histograms Raw Data Grouped Data SurveyeeGenderFavorite Cuisine #1MChinese #2FItalian #3FOther #4MIndian #5MFrench #6MOther #7FChinese #8FOther #9MIndian #10MItalian #11MItalian ……… MFTotal Chinese French Indian Italian Other Total Frequency Table

2. BUS304 – Data Presentation2 Frequency Table  Tells us information on the aggregate level  i.e. How many data fall in one specific category  Such information is most statisticians care about  Can be used to transfer to graphs MFTotal Chinese7310 French224 Indian303 Italian358 Other134 Total161329

3. BUS304 – Data Presentation3 Relative Frequency  Relative Frequency:  The percentage of times MFTotal Chinese7310 French224 Indian303 Italian358 Other134 Total161329 MFTotal Chinese=7/29=3/29=10/29 French=2/29 =4/29 Indian=3/29=0/29=3/29 Italian=3/29=5/29=8/29 Other=1/29=3/29=4/29 Total=16/29=13/291.00

4. BUS304 – Data Presentation4 When data spread to a wide range Raw Data Grouped Data MFTotal 0~$10000 $10000~$20000 $20000~$30000 $30000~$40000 ………… Total Frequency Table SurveyeeGenderAnnual Income #01F90213 #02F35236 #03M45660 #04M61508 #05M24158 #06M57545 #07F61559 #08F57573 ……… We divide the data into ranges andcount how many fall into the range Finish the table and create a barchart to display the grouped dataHint: you may need to sort the rawdata in ascending (or descending) order Finish the table and create a barchart to display the grouped dataHint: you may need to sort the rawdata in ascending (or descending) order

5. BUS304 – Data Presentation5 0~9 10~19 20~29 30~39 40~49 50~59 More Histogram  Also called “frequency histogram”  A bar chart converted from the frequency table:  displays the data distribution:  X-axis shows the data range  Y-axis shows the number of data fall in to the group  Generally don’t have gap between bars Exercise:Adjust the bar chart you havefrom last page to a histogram Exercise:Adjust the bar chart you havefrom last page to a histogram

6. BUS304 – Data Presentation6 Steps to create a histogram 1.Figure out how to group the data  Find the minimal data (rounded down)  Find the maximal data (rounded up)  Find the rough range = max – min  What does the range mean?  Determine how many groups you want to display? (Not too many, but not too few)  Define the Interval (How wide is each group) Interval = (range of Data) / (no. of groups)

7. BUS304 – Data Presentation7 Steps to create a histogram (cont) 2.Write down the boundaries for each group 3.Go to “Tools”  “Data Analysis”  “Histogram” 4.Click “OK” and adjust the space etc. Lower boundUpper bound 1000019999 2000029999 3000039999 4000049999 5000059999 6000069999 7000079999 8000089999 9000099999 Note: some times, the upper bound may look like $19999.99,depending on the decimal of the original data Note: some times, the upper bound may look like $19999.99,depending on the decimal of the original data Raw data List ofUPPER bounds Check this option todisplay the chart

8. BUS304 – Data Presentation8 Extra Notes  The actual shape of the histogram depends on the number of groups  Exercise: try to create a histogram using the income data (data3, sheet2) with 6 groups, 10 groups and 15 groups.  Read: How many people have an annual income higher than $60000? How many are lower than $30000?  Think: What if I only have 2 groups? What if I have 30 groups? Finding the right number of groupsto best present the data distributionmay take you several trials. Finding the right number of groupsto best present the data distributionmay take you several trials.

9. BUS304 – Data Presentation9 Compare two histograms  E.g. Show the differences of distributions between Male and Female Male Female