Lecture 2 - Distributions

Question 1

Type of Variable

“How was your first week of school?”

good, excellent, it was rough, okay

Answer 1

Qualitative - Nominal

No order; Cannot be quantified; Descriptive

Question 2

Shapes of Plots

Answer 2

Question 3

Distributions

Answer 3

A distribution is a table which tells us the frequency of the values of a variable

Question 4

Plots, Charts and Graphs

Graphs

Answer 4

Qualitative graphs

Bar graph, Pie chart

Question 5

Plots, Charts and Graphs

Graphs

Answer 5

Quantitative graphs

Dot plot, Stem and leaf plot, histogram, time series plot, box plot

Question 6

Plots, Charts and Graphs

Bar Graph

Answer 6

Order of the categories is irrelevant

A bar chart doesn’t tell us about the shape because of this

Question 7

Plots, Charts and Graphs

Pie Chart

Answer 7

Not the best way to present data

Question 8

Plots, Charts and Graphs

Dot Plot

Answer 8

1. Place values horizontally in increasing order. Draw a horizontal line above
2. Place a dot for each observed value (stack similar values)
3. Add a title

Question 9

Plots, Charts and Graphs

Stem and Leaf Plot

Answer 9

1. Split data into two parts (stems and leaves).
2. List stems vertically in increasing order. Draw a vertical line to the
   right.
3. Write leaves according to each stem in increasing order.
4. Add a title and legend.

Pros: No loss of information and works well for small datasets

Question 10

Plots, Charts and Graphs

Stem and Leaf Plot

Step 1

Answer 10

1. Split data into two parts (stems and leaves)

Legend: The decimal is ______ digit(s) to the ______ of the |

Question 11

Plots, Charts and Graphs

Histogram

Answer 11

1. Create distribution. Group data into intervals and obtain
   frequencies.
2. Plot it. The x-axis will be the intervals and the y-axis will be the
   frequency (count) or relative frequency (percentage). There are no
   spaces between the bars.

Pros: Works well for large datasets.
Cons: Loss of information when grouping data.

Question 12

Histogram

Interval Considerations

Answer 12

Question 13

Plots, Charts and Graphs

Time Series Plot

Answer 13

Collection of data over a series of time
Look for:

Question 14

Question

Given “Legend: The decimal is two digits to the right of the |” the
number 6|2 would be written as:

A) 0.062
B) 6.2
C) 62
D) 620
E) None of the above

Answer 14

D) 620