Statistics Chapter 2 - Tabular and Graphical Methods

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Statistics Chapter 2 - Tabular and Graphical Methods
2013-04-11 12:17:41
nominal ordinal interval ratio frequency stats

Covers measurement scales and different kinds of frequency distributions
Show Answers:

  1. What are the ways to display qualitative data?
    • Frequency Distribution
    • Relative frequency distribution
    • Bar graph
    • Pie Chart
  2. What measurement scales apply to qualitative data?
    • Nominal
    • Ordinal
  3. How can you display quantitative data?
    • Frequency distribution 
    • Relative frequency distribution
    • Histogram
    • Cumulative distributions
  4. What measurement scales apply to quantitative data?
    • Interval
    • Ratio
  5. How many classes are typically in a frequency distribution?
  6. How do you calculate the width of each class?
    (largest data value - Smallest data value) / Number of classes
  7. What is the class midpoint?
    • The value halfway between the lower and upper class limits
    • Example: 10-14 (12)
  8. What are the 4 rules of frequency distribution classes?
    • Classes can not overlap
    • Classes can not have breaks
    • Each data item must fit into only ONE class
    • Classes must have the same width
  9. What is an open-end class?
    A frequency distribution class that requires only a lower class limit or an upper class limit.
  10. What is a symmetric skew?
    Near perfect bell curve
  11. What is a left or negative skew?
    Longer tail to the left on a histogram.
  12. What is a right or positive skew on a histogram?
    Longer tail to the right.
  13. What is the difference between a histogram and a bar graph?
    A histogram has no spaces between each bar.
  14. What is a cumulative distribution?
    Each value represents the frequency of the current class plus the amounts of all previous classes.
  15. What is a crosstabulation?
    • Tabular summary of 2 variables
    • The variables can be qualitative or quantitative
  16. What are the relevant percentages for crosstabulations?
    • Row
    • Columns
  17. What is Simpson's Paradox?
    Conclusions based on aggregated data may be reversed when we look at unaggregated data.
  18. On a scatter diagram, what does it mean when a trend line moves up from left to right?
    • Both values on the x and y axis are increasing
    • They have a correlation
  19. What does it mean when a trend line moves down from left to right?
    • When x increases, y decreases.
    • There is still a correlation
  20. What does it mean when there is a straight horizontal line?
    The y value has no correlation to x.