Module 4: Visualizing Data

Question 1

Contingency table

Answer 1

-shows frequency or proportion of sampling units in each level of a categorical variable
-the frequency is simply the number of sampling units that falls in each level

Question 2

Contingency table proportions

Answer 2

-help with visualizing the relative distribution of sampling units among the levels

Question 3

One-way and two-way categorical data

Answer 3

-just refer to the number of categorical variables you observe for each sampling unit

Question 4

Marginal distributions

Answer 4

-good way to see overall patterns in data

Question 5

Row marginal distribution

Answer 5

-shows the total counts for each row across columns

Question 6

Column marginal distributions

Answer 6

-shows the total counts for each column across all rows

Question 7

Column marginal distributions

Answer 7

-shows the total counts for each column across all rows

Question 8

To calculate marginal distributions as proportions

Answer 8

-sum all frequencies in the table
-row: sum frequencies across all columns for each row and divide by table total
-column: sum frequencies across all rows for each column and divide by table total

Question 9

Conditional distributions

Answer 9

-shows the interaction between categorical variables (shown as a separate table)
-to create one you first have to select one of the variables to be the primary variable to be the primary and the other to be the secondary (conditional) variable

Question 10

Seeing the pattern

Answer 10

-conditional distributions allow us to see how the secondary variable changes across the primary variable

Question 11

Bar graphs

Answer 11

-can be used to visualize categorical data
-most relevant information should be on the horizontal axis
-two variable bar graphs: first designate one variable as the grouping variable and the create it as a grouped bar chart or stacked bar chart

Question 12

Histograms

Answer 12

-divide numerical data into a number of bins of equal size
-count how many sampling units fit within each bin (frequency)
-create a plot where each bin has a bar with a height equal to the frequency of that bin

Question 13

Box plots

Answer 13

-box: drawn from 1st quartile to 3rd quartile
-solid line: drawn at the median value
-extreme threshold: 1.5 x IQR above and below box
-whiskers: drawn from edge of box plot to last data point within threshold
-extreme values: symbols drawn overtop any data points outside the extreme threshold

Question 14

Scatter plot

Answer 14

-used to visualize the relationship between 2 numerical variables, each point on scatter plot is a sampling unit

Question 15

Line plot

Answer 15

-used when you have data on 2 numerical variables, and where the researcher has taken repeated measures from the same sampling unit (data points are not independent of eachother)