Amagazine claims that 75% of all teenage boys have their own cellphones. a researcher wished to test the claim and selected a random sample of 60 teenage boys. she found that 54 had their own cell phones. at α = 0.01, should the claim be rejected?

Yes, it is a comparison of .75 to .9 (I think?)

1. A geometric sequence has a common ratio. You can find the ratio by dividing every number by its previous one. If it is consistent, then the series is geometric.
a: 8/1=8, 27/8=3.375
b: (-3/2)/3=-1/2, (3/4)/(-3/2)=-1/2
c. 7/4=1.75, 10/7=1.429
d. 20/25=0.8, 14/20=0.7

Choice b is the only one that has a common ratio, so it is a geometric series.

2. Every term is multiplied by 1/3, so the common ratio is 1/3. d is the answer.