Techniques for Summarizing Quantitative Data
Techniques for Summarizing
Quantitative Data frequency histogram
A sample of 40 female statistics students were asked how many times they cried in the previous month.Their replies were as follows:
Stem-Leaf Plot
A natural way to organize (group) quantitative data is with the order property of the real numbers, i.e., arrange the data from least to greatest. For example, the 30 weights: 185, 160, 235, 165, 125, 175, 185, 132, 168, 112, 170, 155, 105, 158, 120, 190, 140, 185, 125, 180, 145, 110, 155 135, 170, 113, 155, 175, 145, 130 are more easily comprehended in order: 105, 110, 112, 113, 120, 125, 125, 130, 132, 135, 140, 145, 145, 155, 155, 155, 158, 160, 165, 168, 170, 170, 175, 175, 180, 185, 185, 185, 190, 235. Note that each weight has been listed as many times as it occurs.
This information can be visually presented with a stem and leaf plot. A position has been chosen to break the numbers into a stem and a leaf. The leaf will always be one digit. The stems are listed on the left, and the corresponding leaves (if any) on the right. Visually a stem-and leaf plot looks like a bar chart; the categories are defined by the decimal structure of the numbers. A stem-and leaf plot for the above data is presented below:
10 | 5 11 | 023 12 | 055 13 | 025 14 | 055 15 | 5558 16 | 058 17 | 0055 18 | 0555 19 | 0 20 | 21 | 22 | 23 | 5 Techniques for Summarizing
Categorical Data
Frequency Table
A frequency table shows the number of occurrences of each category.
Pareto Chart
A bar chart with categories arranged from the highest to the lowest is called a Pareto
Quantitative Data frequency histogram
A sample of 40 female statistics students were asked how many times they cried in the previous month.Their replies were as follows:
Stem-Leaf Plot
A natural way to organize (group) quantitative data is with the order property of the real numbers, i.e., arrange the data from least to greatest. For example, the 30 weights: 185, 160, 235, 165, 125, 175, 185, 132, 168, 112, 170, 155, 105, 158, 120, 190, 140, 185, 125, 180, 145, 110, 155 135, 170, 113, 155, 175, 145, 130 are more easily comprehended in order: 105, 110, 112, 113, 120, 125, 125, 130, 132, 135, 140, 145, 145, 155, 155, 155, 158, 160, 165, 168, 170, 170, 175, 175, 180, 185, 185, 185, 190, 235. Note that each weight has been listed as many times as it occurs.
This information can be visually presented with a stem and leaf plot. A position has been chosen to break the numbers into a stem and a leaf. The leaf will always be one digit. The stems are listed on the left, and the corresponding leaves (if any) on the right. Visually a stem-and leaf plot looks like a bar chart; the categories are defined by the decimal structure of the numbers. A stem-and leaf plot for the above data is presented below:
10 | 5 11 | 023 12 | 055 13 | 025 14 | 055 15 | 5558 16 | 058 17 | 0055 18 | 0555 19 | 0 20 | 21 | 22 | 23 | 5 Techniques for Summarizing
Categorical Data
Frequency Table
A frequency table shows the number of occurrences of each category.
Pareto Chart
A bar chart with categories arranged from the highest to the lowest is called a Pareto