In a survey, 70 out of 84 people from the north prefer professional football over college football. 120 people from the south were asked the same question. In order for favorite type of football and region to be independent, how many people in the south would have to prefer professional football

Around 100 people will answer that they prefer professional football.

Step-by-step explanation:

In the north, 70 out of 84 prefer professional football, then the relative frequency is

p = 70/84 = 0.83

Now, in the south, they asked to 120 people, and we can assume that the relative frequency will be about the same than in the north (because the relation is independent, which means that the region does not affect on the answer to the question of if they prefer professional or college football), so we have that if X people prefer professional football, we have:

p = X/120 = 0.83

X = 120*0.83 = 100

So around 100 people will answer that they prefer professional football.