Question

automobile ownership
seat - belt usage across different road types
road type | yes | no | total
highway | 70 | 30 | 100
city | 50 | 50 | 100
rural | 60 | 40 | 100
total | 180 | 120 | 300
what is the marginal frequency of drivers who said \yes\ to using seat belts across all road types?
60%
180%
60
180

Explanation:

Step1: Understand Marginal Frequency

Marginal frequency for a category (here, "Yes" for seat - belt use) is the total number of observations in that category across all groups (road types).

Step2: Locate the "Yes" Total

In the contingency table, the "Total" row for the "Yes" column gives the marginal frequency. From the table, the value in the "Total" row and "Yes" column is 180.

Answer:

180