Chapter 2

Question 1

What can we do with qualitative data?

Answer 1

1. frequency distributions
2. Relative frequency
3. Percentages
4. Graphs

Question 2

Frequency

Answer 2

Count of how often each category occurs

Question 3

Relative frequency

Answer 3

Frequency/sum of all frequencies

Question 4

Percentage

Answer 4

Relative frequency x 100%

Question 5

Bar graph

Answer 5

A graph made of bars whose heights represent the frequencies of respective categories.

Question 6

Pareto chart

Answer 6

A bar graph with bars arranged by their heights in descending order.

Question 7

Pie chart

Answer 7

A circle divided into portions that represent the relative frequencys or percentages belonging to different categories.

Question 8

3 ways to graph qualitative data

Answer 8

l. Pie chart
2. Bar graph
3. Pareto chart

Question 9

3 major decisions when constructing a frequency table

Answer 9

1. Number of classes (how many groups)
2. class width ((largest value - smallest value) / number of classes)
3. Lower limit of the first class (must be less than or equal to our numerical data)

Question 10

Histogram

Answer 10

A graph in which classes are marked on the horizontal axis and the frequencies, or percentages are marked on the vertical axis. Drawn with no spaces.

Question 11

Polygon

Answer 11

A graph formed by joining the midpoints of the tops of successive bars in a histogram w/ straight lines.

Question 12

Frequency distribution curve

Answer 12

For large data sets, a polygon can eventually become a smooth curve.

Question 13

Less-than class method for histograms

Answer 13

Avoids the gap between classes.
Slightly shifts the upper-limit, so they are just “less than” the next lower limit.
Useful for data sets that contain fractional values (continuous data types).

Question 14

Single-valued classes

Answer 14

When your data only consists of a few distinct values.
Treats your data as qualitative instead of quantitative.

Question 15

Types of graphs for quantitative data

Answer 15

1. Histogram
2. Polygon
3. Frequency curve

Question 16

Cumulative frequency

Answer 16

Gives the total number of values that fall below the upper boundary of each class.

Question 17

Shapes of histograms

Answer 17

1. Symmetric (mirror image)
2. Skewed (right or left)
3. Uniform

Question 18

Truncating axes

Answer 18

Graphs can distort the data (intentionally or unintentionally) to make things seem more extreme.

Question 19

Stem and leaf displays

Answer 19

Displays quantitative data values divided into two portions.
1. The leaf - second digit
2. The stem - first digit
The leaves are typically reordered to sort them.

Question 20

Grouped stem-and-leaf displays

Answer 20

Useful when you want less stems and more leaves.
Can separate the digits in certain classes with a “*”.

Question 21

Splitting stem + leaf displays

Answer 21

A stem can be used multiples times to break the leaves into groups.
Useful when you want more stems and less leaves.
See more detail, distributions and peaks.

Question 22

Dotplots

Answer 22

Horizontal axis consists of values of variables.
Each dot represents a data point.
Similar to a bar graph, but height is shown using dots.
Can be useful for detecting outliers/ extreme values.