Chapter 2

Question 1

What are the types of data

Answer 1

1. categorical

2. quantitative

Question 2

What are the types of displays for categorical Data?

Answer 2

1. Tabular - frequency distribution table
2. Graphical
   1. Bar chart
   2. Pie chart

Question 3

How many frequency are there in a frequency distribution

Answer 3

of observations

Question 4

What does all of the relative frequency’s add up to

Answer 4

1

Question 5

What does all of the % frequency’s add up to

Answer 5

100

Question 6

What are the types of displays for Quantitative data

Answer 6

1. tabular - frequency distribution
2. graphical
   1. Dot Plot
   2. Histogram
   3. stem and leaf

Question 7

What are the steps for a frequency distribution table for Quantitative Data?

Answer 7

step 1: decide on how many nonoverlapping categories
(5-20)
Step 2: determine the width of each category
(largest vale - smallest value ) / # of categories
Step 3: determine the class limits (upper and lower)

Question 8

Describe the Dot Plot

Answer 8

1. shows the distribution of quantitative data over the entire RANGE of the data
2. it is the simplest

Question 9

Describe Histogram

Answer 9

1. shows the frequency distribution for quantitative data over a set of class intervals
2. most commonly used

Question 10

Describe the Stem and leaf plot and what does it show?

Answer 10

1. provides more data than the histogram

2. shows order, rank and shape

Question 11

what are the advantages of stem and leaf

Answer 11

1. easier to construct by hand

2. w/in a class interval, provides more info b/c stem and leaf shows the actual data

Question 12

What do you use to summarize two variables?

Answer 12

1. crosstabulations

2. graphical - scatter diagrams

Question 13

explain crosstabulations

Answer 13

1. a tabular summary of of 2 variables
2. can be quantitative or categorical data
3. margins provide info about each variable individually
   4 it does not show the relationship b/w variables
4. Primary value - to provide insight into the relationship b/w 2 variables

Question 14

What is Simpson’s Paradox

Answer 14

• it is the reversal of conclusions based on aggregated and unaggregated data
• make sure you investigate whether aggregate or unaggregated provides better insight in the cross tabs

Question 15

How can you display 2 variables graphically

Answer 15

• use a scatter diagram

Question 16

Describe a scatter diagram

Answer 16

• graphical display of the relationship b/w 2 quantitative variables

Question 17

why is a scatter diagram more useful than crosstabulation

Answer 17

• more useful for recognizing the patters and trends,

- can help us make common sense inferences b/c we can usually compare, contrast and recognize patterns

Question 18

What are trendlines

Answer 18

• used in scatter diagram
• it’s a line that produces an approximation of the relationship b/w 2 variables
• positive relationship
• negative relationship
• no apparent relationship

Question 19

What do you need to create effective graphical displays

Answer 19

1. clear and concise TITLE
2. keep the display simple
3. clearly label each axis and provide the units of measure
4. use distinct colours to distinguish categories
5. if using multiple colours or line types, use a legend
   
   • place the legend close to the data (Chart)

Question 20

What are the displays used to show comparisons?

Answer 20

1. side by side chart - used to compare 2 variables

2. stacked bar chart - used to compare the Rel Freq. or % Freq. of 2 variables

Question 21

What can you use if you have multiple variables and what is the recommendation

Answer 21

1. radar charts and bubble charts
2. recommend not using them b/c they an be over complicated
   - instead, use bar charts and scatter diagrams

Question 22

What are the measures of location

Answer 22

1. Mean
2. WEighted Mean
3. Geometric Mean
4. Median
5. Mode
6. Percentile
7. Quartile