Which of the following samples would constitute a biased sample?

Seventh grade girls were randomly surveyed to determine what theme the whole school would prefer for the dance.
A tele-market research company randomly called and surveyed one thousand men and women over the age of 65 to determine which insurance companies were preferred in retirement.
Kids at a large preschool were randomly surveyed to determine the color most preschoolers like best at that school.
Two thousand people were randomly surveyed about their favorite candy in four different cities in Arizona to determine Arizona’s favorite candy.

Seventh grade girls were randomly surveyed to determine what theme the whole school would prefer for the dance.

Step-by-step explanation:

-This method of sampling is systematically different from the population( whole school).

-It favors some outcomes over the others. Seventh grade preferences have a 100% chance of being played over other grade's preferences.

-The sample only truly represent's seventh grade as opposed to the whole school.

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step-by-step explanation:

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: