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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. Qualitative vs. Quantitative (Different tools for different data). Question 1: Type of skin cancer A: Qualitative B: Quantitative.
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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
Qualitative vs. Quantitative (Different tools for different data) • Question 1: Type of skin cancer • A: Qualitative • B: Quantitative
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
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
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!
Frequency: A fancy word for “count” • Distribution: A way to describe how likely certain values are to be observed.
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
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.
Which is a relative frequency table?Statistics 108 students’ class standings (n=79) A B
These graphs are: bar graphs histograms Which graph is the relative frequency graph? (A) top graph (B) bottom graph
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.
Use the below data to calculate degrees of the sophomore slice. 12 degrees 0.15 degrees 15 degrees 55 degrees
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.
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
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 • 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 • 2, 3, 4, 5, 8, 8, 9, 10, 10, 10, 11, 13, 14, 14, 14, 14, 15, 17, 18, 20, 20 • 234, 5889, 1000, 1001, 1003, 1004, 1004, 1004, 1004, 1004, 1587, 200 • 0.234, 0.5889, 1.000134444, 1.578, 2.00
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