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Ch 2 - Descriptive Statistics and Data Display in Business Statistics

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Terms in this set (20)

  • What is a frequency distribution?
    A frequency distribution is a table showing the number of data observations in specific intervals or classes, organizing raw data into meaningful groups.
  • How do you calculate class width in a frequency distribution?
    Class width = \(\frac{\text{Max Value} - \text{Min Value}}{k}\), where k is the number of classes.
  • What is the formula for relative frequency?
    Relative frequency = \(\frac{\text{Class Frequency}}{\text{Total Observations}}\), showing the proportion of observations in each class.
  • What does a cumulative relative frequency distribution represent?
    It totals the proportion of observations less than or equal to a given class, calculated as the sum of relative frequencies up to that class.
  • Describe a histogram and its characteristics.
    A histogram is a bar graph for quantitative data where bars touch, representing frequency of classes. It shows data distribution shapes like symmetric or skewed.
  • What is the difference between a polygon and an ogive?
    A polygon connects class midpoints with frequencies as points, while an ogive graphs cumulative frequencies to identify medians and percentiles.
  • What is a stem and leaf display used for?
    It splits data into stems (larger place values) and leaves (smaller place values) to graphically describe distribution while preserving original data.
  • What is the purpose of a scatter plot?
    A scatter plot visually shows the relationship between two quantitative variables, helping identify correlation and trends.
  • When is a line chart typically used?
    A line chart connects data points over time to show trends or changes in a quantitative variable.
  • How is frequency distribution applied to qualitative data?
    It shows counts and proportions for categories, organizing qualitative data like grades or survey responses.
  • What is a bar chart used for in qualitative data?
    A bar chart displays frequencies or proportions of categories, useful for comparing qualitative data values.
  • What distinguishes a Pareto chart?
    A Pareto chart is a bar chart with categories in descending frequency order, including a cumulative frequency line, often used in quality control.
  • What is the function of a pie chart?
    A pie chart compares proportions of categories in qualitative data, with each slice representing a category's share of the total.
  • What does a contingency table show?
    It displays frequencies of two qualitative variables, showing the breakdown of one variable in terms of another to analyze relationships.
  • How do you activate the Analysis ToolPak in Excel?
    Go to File > Options > Add-Ins > Manage Excel Add-ins > Go > Check Analysis ToolPak > OK.
  • How do you construct a frequency table in Excel?
    Use the FREQUENCY function: \(=\text{FREQUENCY}(\text{data range}, \text{bin range})\) or use Data Analysis > Histogram.
  • What is the main objective of a frequency table?
    To organize and summarize quantitative or qualitative data by showing the number of observations in each class or category.
  • What type of data is best displayed with a histogram?
    Quantitative data, showing the distribution of variable values across classes.
  • What type of data is best displayed with a bar chart or pie chart?
    Qualitative (categorical) data, to compare frequencies or proportions across categories.
  • What is the formula for the number of classes using the rule of thumb?
    Number of classes \(>= 2 \sqrt{n}\), where n is the number of data points.