MODULE 4 - VISUALIZING DATA

Question 1

what is a contingency table?

Answer 1

tables of data frequencies or proportions within different levels of categorical variabl

Question 2

what is frequency?

Answer 2

the number of sampling units that falls in each level

Question 3

what are one-way contingency tables?

Answer 3

or data with a single categorical variable and are shown as a one-dimensional table of columns

Question 4

what are two-way contingency tables?

Answer 4

for data with two categorical variables and are shown as a two-dimensional table of rows and columns

Question 5

what are marginal distributions?

Answer 5

the row and column sums of a two-way contingency table

they can be shown as frequencies or proportions

Question 6

how to calculate marginal distributions as frequencies

Answer 6

row: sum frequencies across all columns for each row

column: sum frequencies across all rows for each column

Question 7

how to calculate marginal distributions as proportions

Answer 7

table total: 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 8

what are conditional distributions?

Answer 8

are two-way tables that show the proportion of sampling units for one variable within each level of the second variable

Question 9

how to calculate conditional distributions

Answer 9

1. Identify the primary versus secondary variable. This determines whether you use the row or column marginal distribution
2. For each cell in the new table, divide the value from the contingency table by the marginal distribution of the primary variable.

Question 10

advantages/disadvantages to a histogram

Answer 10

pros: provide a great way to visualize the pattern of relative abundance in your sampling units along the numerical variable

cons: that it is cumbersome to display histograms when your dataset also has multiple levels of a categorical variable

Question 11

what is a bin?

Answer 11

a small range of the numerical variable

Question 12

4 parts to a box plot

Answer 12

1. box
2. solid line
3. whiskers
4. extreme values