chapter 2
DESCRIPTION
Chapter 2. Section 2.1: Organizing qualitative data Section 2.2: Organizing quantitative data Section 2.3: skip Section 2.4: Misrepresentations of data. Qualitative vs. Quantitative (Different tools for different data). Question 1: Type of skin cancer A: Qualitative B: Quantitative. - PowerPoint PPT PresentationTRANSCRIPT
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Chapter 2
• Section 2.1: Organizing qualitative data• Section 2.2: Organizing quantitative data• Section 2.3: skip• Section 2.4: Misrepresentations of data
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Qualitative vs. Quantitative (Different tools for different data)
• Question 1: Type of skin cancer– A: Qualitative– B: Quantitative
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Qualitative vs. Quantitative (Different tools for different data)
• Question 1: Type of skin cancer– A: Qualitative– B: Quantitative
• Question 2: Quarterly profit – A: Qualitative– B: Quantitative
![Page 4: Chapter 2](https://reader036.vdocuments.us/reader036/viewer/2022062520/568164f0550346895dd75bbc/html5/thumbnails/4.jpg)
Qualitative vs. Quantitative (Different tools for different data)
• Question 1: Type of skin cancer– A: Qualitative– B: Quantitative
• Question 2: Quarterly profit – A: Qualitative– B: Quantitative
• Question 3: Customer satisfaction– A: Qualitative– B: Quantitative
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Qualitative vs. Quantitative (Different tools for different data)
• Question 1: Type of skin cancer– A: Qualitative– B: Quantitative
• Question 2: Quarterly profit – A: Qualitative– B: Quantitative
• Question 3: Customer satisfaction– A: Qualitative (poor, moderate, high)– B: Quantitative (1,2,3,4,5,6,7,8,9,10)
It isn’t always totally clear!
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• Frequency: A fancy word for “count”
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• Frequency: A fancy word for “count”• Distribution: A way to describe how likely
certain values are to be observed.
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• Frequency: A fancy word for “count”• Distribution: A way to describe how likely
certain values are to be observed.• Frequency distribution: A list tabulating the
number of occurrences for each category
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• Frequency: A fancy word for “count”• Distribution: A way to describe how likely
certain values are to be observed.• Frequency distribution: A list tabulating the
number of occurrences for each category• Relative frequency distribution: A frequency
distribution that uses proportions instead of counts.
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Which is a relative frequency table?Statistics 108 students’ class standings (n=79)
Class standingFreshmen 0.5000
Sophomore 0.1500
Junior 0.1750
Senior 0.1625
A
B
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SophomoreSeniorJuniorFreshman
50
40
30
20
10
0
Class
Perc
ent
Stat 108 students
Percent within all data.
These graphs are:(A)bar graphs (B)histograms
Which graph is the relative frequency graph? (A) top graph(B) bottom graph
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• The only difference between a frequency bar graph and a relative frequency bar graph is the labeling of the y-axis. (Likewise for histograms.)
• Relative frequency saves the reader calculations
• Frequency graphs tell the reader the actual counts.
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A pie chart of the data
Fr
So
Jr
Sr
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Use the below data to calculate degrees of the sophomore slice.
(A)12 degrees(B)0.15 degrees(C)15 degrees(D)55 degrees
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Histograms
• Histograms are for quantitative data• “Classes” or “bins” are which data are
grouped into.• Upper and lower limit for each class/bin is
subjective.• Goal: Summarize data, but leave some detail.
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Histograms of sparrow weights
Moderate number of bins
Freq
uenc
y
22 24 26 28 30 32
010
20
lots of bins
Freq
uenc
y
22 24 26 28 30 32
05
1015
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Weights of 87 sparrows (grams)23.2 23.3 23.3 23.5 23.6 23.7 23.8 23.9 24 24.1 24.2 24.3 24.3 24.3 24.4 24.5 24.6 24.6 24.6 24.6 24.7 24.7 24.7 24.8 24.8 24.9 24.9 24.9 25 25 25 25.1 25.4 25.5 25.5 25.6 25.6 25.6 25.7 25.7 25.7 25.7 25.7 25.8 25.9 25.9 26 26 26 26 26 26.1 26.1 26.2 26.2 26.3 26.3 26.4 26.5 26.5 26.5 26.5 26.6 26.6 26.7 26.7 26.7 26.8 26.8 26.9 26.9 26.9 26.9 27 27 27.1 27.3 27.5 27.5 27.6 27.9 28 28.3 28.3 28.6 29 31
Stem-and-leaf plot
In the below software’s stem-and-leaf plot, the decimal point is at the | Displays vary slightly across statistical software
23 | 23356789 24 | 01233345666677788999 25 | 000145566677777899 26 | 000001122334555566777889999 27 | 00135569 28 | 0336 29 | 0 30 | 31 | 0
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Determine the original data set:(The decimal point is 1 digit(s) to the right of the |)
0| 234 0 | 5889 1 | 000134444 1 | 578 2 | 00(A) 0.2, 0.3, 0.4, 0.5, 0.8, 0.8, 0.9, 1, 1, 1, 1.1, 1.3, 1.4, 1.4, 1.4, 1.4, 1.5, 1.7,
1.8, 2, 2 (B) 2, 3, 4, 5, 8, 8, 9, 10, 10, 10, 11, 13, 14, 14, 14, 14, 15, 17, 18, 20, 20(C) 234, 5889, 1000, 1001, 1003, 1004, 1004, 1004, 1004, 1004, 1587, 200(D) 0.234, 0.5889, 1.000134444, 1.578, 2.00
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Create a stem-and-leaf plot for values:24,25,26,29,29,30,31,31,35,36,36
2 | 4 2 | 5699 3 | 011 3 | 566
2 | 45699 3 | 011566
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Dot Plot
Sparrow weights (grams)
Cou
nt
0
5
10
15
20
25
24 26 28 30
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Bad graphs…
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