Chapter 2. Describing Data Ir.Muhril Ardiansyah,M.Sc.,Ph.D.1 Chapter 2. Describing Data
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Chapter 2. Descri bing Data Ir.Muhril Ardiansyah,M.Sc.,Ph .D. 1 Chapter 2. Describing Data http:// statisticdescriptive.wordpress.com/
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Transcript of Chapter 2. Describing Data Ir.Muhril Ardiansyah,M.Sc.,Ph.D.1 Chapter 2. Describing Data
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 1
Chapter 2.Describing Data
http://statisticdescriptive.wordpress.com/
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 2
Constructing A Frequency Table Frequency table: a grouping of qualitative data into mutually
exclusive classes showing the number of observation in each class.
Class frequency: the number observations in each class
Table 2-1 Page 22
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 3
Table 2-1 Frequency Table For Vehicles Sold At Whitner Autoplex Last Month
Car Type Number Of Car
Domestic 50
Foreign 30
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 4
Constructing A Frequency Table (continued)
Relative class frequencies: show the fraction of the total number
of observation in each class.
Table 2-2 Page 23
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 5
Table 2-2 Relative Frequency Table Of Vehicles Sold
Vehicle Type Number Sold Relative Frequency
Domestic 50 50/80 =0.625
Foreign 30 30/80=0.375
Total 80 80/80=1
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 6
Constructing A Frequency Table (continued)
Graphic presentation of qualitative data: - bar chart a graph in which the classes are reported on the horizontal axis, and the class frequencies on the vertical axis.
Chart 2-1 Page 23
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 7
Constructing A Frequency Table (continued)
Graphic presentation of qualitative data: - Pie chart a chart that shows the proportion or percent that each class represents of the total number of frequencies.
Chart 2-2 Page 24
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 8
Constructing Frequency Distributions: Quantitative Data
Frequency distribution: a grouping of data into mutually
exclusive classes showing the number of observations in each class.
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 9
Table 2-4 Page 28Prices of vehicles sold last month at Whitner Autoplex
$23197 $23372 $20454 $26651……………………………………………………
………………………………………………………………
………..n = 80
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 10
The Steps For Organizing Data Into A Frequency Distribution Step 1: Decide on the number of classes. Step 2: Determine the class interval or width. Step 3: Set the individual class limits. Step 4: Tally the vehicle selling prices into the classes. Step 5: Count the number of items in each class.
Chapter 2. Describing Data
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Step 1: Decide on the number of classes
n = 80
If k = 6 (k is number of classes)Then: 2k
26 = 64, still less than 80 not using k =6
If k = 7Then: 2k
27 = 128, greater than 80Decide at least k = 7Can choose k more than 7
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 12
Step 2: Determine the class interval or width
i more or equal (H – L)/ ki = class intervalH = the highest observed valueL = the lowest observed value
H = 35925L = 15546i = (35925-15546)/7 = 2911 = 3000
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 13
Step 3: Set the individual class limits
15000 up to 1800018000 up to 2100021000 up to 2400024000 up to 2700027000 up to 3000030000 up to 3300033000 up to 36000
Chapter 2. Describing Data
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Step 4: Tally the vehicle selling prices into the classes
Class Tallies15000 up to 18000 IIIII III18000 up to 21000 IIIII IIIII IIIII IIIII III21000 up to 24000 IIIII IIIII IIIII II24000 up to 27000 IIIII IIIII IIIII III27000 up to 30000 IIIII III30000 up to 33000 IIII33000 up to 36000 II
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Step 5: Count the number of items in each class
Selling Price Frequency15000 up to 18000 818000 up to 21000 2321000 up to 24000 1724000 up to 27000 1827000 up to 30000 830000 up to 33000 433000 up to 36000 2TOTAL 80
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 16
Class Intervals And Class Midpoints
Chapter 2. Describing Data
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Relative Frequency Distribution
A relative frequency distribution: converts the frequency to a percent.
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 18
Selling Price Frequency Relative Freq15000 up to 18000 8 0.118000 up to 21000 23 0.287521000 up to 24000 17 0.212524000 up to 27000 18 0.225027000 up to 30000 8 0.130000 up to 33000 4 0.0533000 up to 36000 2 0.025TOTAL 80 1.00
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 19
Graphic Presentation Of A Frequency Distribution:
1. Histogram.2. Frequency polygon.
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 20
Histogram: a graph in which the classes are
marked on the horizontal axis and the class frequencies on the vertical axis. The class frequencies are represented by the heights of the bars and the bars are drawn adjacent to each other.
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 21
Frequency polygon: the class midpoints are connected
with a line segment.
Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 22
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Chapter 2. Describing Data
Ir.Muhril Ardiansyah,M.Sc.,Ph.D. 23
Quiz
The following is the number of minutes to commute from home to work for a group of automobile executives;28 25 48 37 41 19 32 26 16 23 23 29 36 31 26 21 32 25 31 43 35 42 38 33 28Make frequency distribution included relative freq.
