Chapter 1: Picturing Distributions

Question 1

Distribution:

Answer 1

• Description of what values a variable takes and how often it takes them
• Expressed as a table, graph, or function

Question 2

Displaying Distributions w/Categorical Variables

Answer 2

• Pie charts: better for comparing group sizes to total

- Bar graphs: Better for comparing grp sizes to each other

Question 3

Main characteristics of a Distribution

Answer 3

• Centre (average)
• Spread (variation)
• Distribution (shape)

Question 4

Distribution options

Answer 4

• Symmetric

- Asymmetric (left of right skewed: that end of distribution is further f/peak)

Question 5

Outliers

Answer 5

-Extreme values that fall outside overall pattern

Question 6

Groupings for histograms (determining class intervals)

Answer 6

• How many class intervals? square root of sample size
• How wide: divide range by number of intervals
• Too few: info lost. Too many: pattern lost