Question

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?
180%
180
60
60%

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. We look at the "Total" row and "Yes" column in the table.

Step2: Identify the Value

From the table, in the "Total" row and "Yes" column, the value is 180. The 180% is incorrect as frequency is a count (or proportion, but here the total count of "Yes" is 180), 60 is the number of rural drivers who said "Yes" (not the total across all road types), and 60% would be a relative frequency (180/300 = 0.6 or 60%, but the question asks for marginal frequency which is the count here).

Answer:

180