A researcher wants to determine what percent of all first graders who believe unicorns are real. She obtains a database of all current first graders in the USA, and sorts the database by the county in which the child attends school. She randomly selects 25 counties, and includes all first graders in each of them to form her sample. The sampling technique used by this researcher is:

the answer is stop cheating on things stoopid

step-by-step explanation:

im eatin up the 44

to have more of what you want like money

step-by-step explanation:

save it by not spending on unnecessary stuff and have more

24 units

step-by-step explanation:

1. sometimes

2.   never

3   .08c = 7.50+.05c   250 pages

step-by-step explanation:

1.   sometimes

the theoretical probability of rolling a 1 is 1/6.   perhaps you got really lucky and never rolled a 1   in those 60 times.   your experimental probability is 0.   or perhaps you rolled a 1   20 times.   your experimental probability is 20/60 is 1/3.     it really just depends on how you rolled in that experiment.

2.   never

the probability of the event occurring is 1.   that is being 100 % sure it will happen.   that is the maximum amount of confidence we have.

3.   no customer card cost:   .08 times number of pages

customer card cost:   7.50 + .05 times number of pages

we want to find when it costs the same amount, so we will set these equal

let c = number of pages

.08c = 7.50+.05c

subtract .05c from each side

.08c-.05c = 7.5+.05c-.05c

.03c=7.5

divide each side by .03

.03c/.03 = 7.5/03

c =250  

the cost is the same at 250 pages