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MBA 604 Introduction Probaility and Statistics Lecture Notes

MBA 604 Introduction Probaility and Statistics Lecture Notes

MBA 604 Introduction Probaility and Statistics Lecture Notes

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2 Graphical Methods<br />

Frequency <strong>and</strong> relative frequency distributions (Histograms):<br />

Example<br />

Weight Loss Data<br />

20.5 19.5 15.6 24.1 9.9<br />

15.4 12.7 5.4 17.0 28.6<br />

16.9 7.8 23.3 11.8 18.4<br />

13.4 14.3 19.2 9.2 16.8<br />

8.8 22.1 20.8 12.6 15.9<br />

Objective: Provide a useful summary of the available information.<br />

Method: Construct a statistical graph called a “histogram” (or frequency distribution)<br />

Weight Loss Data<br />

class bound- tally class rel.<br />

aries freq, f freq, f/n<br />

1 5.0-9.0- 3 3/25 (.12)<br />

2 9.0-13.0- 5 5/25 (.20)<br />

3 13.0-17.0- 7 7/25 (.28)<br />

4 17.0-21.0- 6 6/25 (.24)<br />

5 21.0-25.0- 3 3/25 (.12)<br />

6 25.0-29.0 1 1/25 (.04)<br />

Totals 25 1.00<br />

Let<br />

k = # of classes<br />

max = largest measurement<br />

min = smallest measurement<br />

n =samplesize<br />

w =classwidth<br />

Rule of thumb:<br />

-The number of classes chosen is usually between 5 <strong>and</strong> 20. (Most of the time between<br />

7 <strong>and</strong> 13.)<br />

-The more data one has the larger is the number of classes.<br />

7

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