Chapter 4: Displaying Quantitative Data

Question 1

bins

Answer 1

-equal width sections of quantitative variables (5-10, 10-15, etc.)

Question 2

distribution

Answer 2

-bins and the counts in each bin give the distribution of the variable

Question 3

histogram

Answer 3

• plots bin counts as height of the bars (values exactly on a bin boundary are on the bin to the right)
• no spaces between bars

Question 4

relative frequency histogram

Answer 4

-displays percentage of cases in each bin, instead of the count

Question 5

stem and leaf plot

Answer 5

• used instead of histograms for smaller sets of data
• created by John W. Tukey
• leading digits: stem
• trailing digits: leaves
• satisfy the are principle and show distribution by preserving the actual values

Question 6

dotplot

Answer 6

• one dot per case in the data

- some up and down, some side-to-side

Question 7

3 terms to describe displays

Answer 7

-shape, center, spread

Question 8

mode

Answer 8

• creates a hump on a histogram bc it appears the most
• unimodal: one main peak
• bimodal: 2 peaks
• multimodal: 3 or more peaks

Question 9

uniform

Answer 9

-histogram with no apparent mode

Question 10

symmetry

Answer 10

-used to describe histograms

Question 11

skewed

Answer 11

-one tail (thinner end) stretches out farther than the other

Question 12

outliers

Answer 12

-data that is away from the body of distribution

Question 13

gaps

Answer 13

-data may not homogeneous

Question 14

timeplot

Answer 14

-displays time vs another variable to see the volatility

Question 15

re-express/transform

Answer 15

• makes skewed distribution more symmetric by applying a simple function
• ex: square root or log a function
• left skew: square
• right skew: log or square root